使用 AWS SDK for .NET 的 DynamoDB 示例

using Amazon.DynamoDBv2;
using Amazon.DynamoDBv2.Model;

namespace DynamoDB_Actions;

public static class HelloDynamoDB
{
    static async Task Main(string[] args)
    {
        var dynamoDbClient = new AmazonDynamoDBClient();

        Console.WriteLine($"Hello Amazon Dynamo DB! Following are some of your tables:");
        Console.WriteLine();

        // You can use await and any of the async methods to get a response.
        // Let's get the first five tables.
        var response = await dynamoDbClient.ListTablesAsync(
            new ListTablesRequest()
            {
                Limit = 5
            });

        foreach (var table in response.TableNames)
        {
            Console.WriteLine($"\tTable: {table}");
            Console.WriteLine();
        }
    }
}

        /// <summary>
        /// Creates a new Amazon DynamoDB table and then waits for the new
        /// table to become active.
        /// </summary>
        /// <param name="client">An initialized Amazon DynamoDB client object.</param>
        /// <param name="tableName">The name of the table to create.</param>
        /// <returns>A Boolean value indicating the success of the operation.</returns>
        public static async Task<bool> CreateMovieTableAsync(AmazonDynamoDBClient client, string tableName)
        {
            var response = await client.CreateTableAsync(new CreateTableRequest
            {
                TableName = tableName,
                AttributeDefinitions = new List<AttributeDefinition>()
                {
                    new AttributeDefinition
                    {
                        AttributeName = "title",
                        AttributeType = ScalarAttributeType.S,
                    },
                    new AttributeDefinition
                    {
                        AttributeName = "year",
                        AttributeType = ScalarAttributeType.N,
                    },
                },
                KeySchema = new List<KeySchemaElement>()
                {
                    new KeySchemaElement
                    {
                        AttributeName = "year",
                        KeyType = KeyType.HASH,
                    },
                    new KeySchemaElement
                    {
                        AttributeName = "title",
                        KeyType = KeyType.RANGE,
                    },
                },
                ProvisionedThroughput = new ProvisionedThroughput
                {
                    ReadCapacityUnits = 5,
                    WriteCapacityUnits = 5,
                },
            });

            // Wait until the table is ACTIVE and then report success.
            Console.Write("Waiting for table to become active...");

            var request = new DescribeTableRequest
            {
                TableName = response.TableDescription.TableName,
            };

            TableStatus status;

            int sleepDuration = 2000;

            do
            {
                System.Threading.Thread.Sleep(sleepDuration);

                var describeTableResponse = await client.DescribeTableAsync(request);
                status = describeTableResponse.Table.TableStatus;

                Console.Write(".");
            }
            while (status != "ACTIVE");

            return status == TableStatus.ACTIVE;
        }

        public static async Task<bool> DeleteTableAsync(AmazonDynamoDBClient client, string tableName)
        {
            var request = new DeleteTableRequest
            {
                TableName = tableName,
            };

            var response = await client.DeleteTableAsync(request);
            if (response.HttpStatusCode == System.Net.HttpStatusCode.OK)
            {
                Console.WriteLine($"Table {response.TableDescription.TableName} successfully deleted.");
                return true;
            }
            else
            {
                Console.WriteLine("Could not delete table.");
                return false;
            }
        }

        /// <summary>
        /// Deletes a single item from a DynamoDB table.
        /// </summary>
        /// <param name="client">The initialized DynamoDB client object.</param>
        /// <param name="tableName">The name of the table from which the item
        /// will be deleted.</param>
        /// <param name="movieToDelete">A movie object containing the title and
        /// year of the movie to delete.</param>
        /// <returns>A Boolean value indicating the success or failure of the
        /// delete operation.</returns>
        public static async Task<bool> DeleteItemAsync(
            AmazonDynamoDBClient client,
            string tableName,
            Movie movieToDelete)
        {
            var key = new Dictionary<string, AttributeValue>
            {
                ["title"] = new AttributeValue { S = movieToDelete.Title },
                ["year"] = new AttributeValue { N = movieToDelete.Year.ToString() },
            };

            var request = new DeleteItemRequest
            {
                TableName = tableName,
                Key = key,
            };

            var response = await client.DeleteItemAsync(request);
            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }

using System;
using System.Collections.Generic;
using Amazon.DynamoDBv2;
using Amazon.DynamoDBv2.Model;

namespace LowLevelBatchGet
{
    public class LowLevelBatchGet
    {
        private static readonly string _table1Name = "Forum";
        private static readonly string _table2Name = "Thread";

        public static async void RetrieveMultipleItemsBatchGet(AmazonDynamoDBClient client)
        {
            var request = new BatchGetItemRequest
            {
                RequestItems = new Dictionary<string, KeysAndAttributes>()
            {
                { _table1Name,
                  new KeysAndAttributes
                  {
                      Keys = new List<Dictionary<string, AttributeValue> >()
                      {
                          new Dictionary<string, AttributeValue>()
                          {
                              { "Name", new AttributeValue {
                            S = "Amazon DynamoDB"
                        } }
                          },
                          new Dictionary<string, AttributeValue>()
                          {
                              { "Name", new AttributeValue {
                            S = "Amazon S3"
                        } }
                          }
                      }
                  }},
                {
                    _table2Name,
                    new KeysAndAttributes
                    {
                        Keys = new List<Dictionary<string, AttributeValue> >()
                        {
                            new Dictionary<string, AttributeValue>()
                            {
                                { "ForumName", new AttributeValue {
                                      S = "Amazon DynamoDB"
                                  } },
                                { "Subject", new AttributeValue {
                                      S = "DynamoDB Thread 1"
                                  } }
                            },
                            new Dictionary<string, AttributeValue>()
                            {
                                { "ForumName", new AttributeValue {
                                      S = "Amazon DynamoDB"
                                  } },
                                { "Subject", new AttributeValue {
                                      S = "DynamoDB Thread 2"
                                  } }
                            },
                            new Dictionary<string, AttributeValue>()
                            {
                                { "ForumName", new AttributeValue {
                                      S = "Amazon S3"
                                  } },
                                { "Subject", new AttributeValue {
                                      S = "S3 Thread 1"
                                  } }
                            }
                        }
                    }
                }
            }
            };

            BatchGetItemResponse response;
            do
            {
                Console.WriteLine("Making request");
                response = await client.BatchGetItemAsync(request);

                // Check the response.
                var responses = response.Responses; // Attribute list in the response.

                foreach (var tableResponse in responses)
                {
                    var tableResults = tableResponse.Value;
                    Console.WriteLine("Items retrieved from table {0}", tableResponse.Key);
                    foreach (var item1 in tableResults)
                    {
                        PrintItem(item1);
                    }
                }

                // Any unprocessed keys? could happen if you exceed ProvisionedThroughput or some other error.
                Dictionary<string, KeysAndAttributes> unprocessedKeys = response.UnprocessedKeys;
                foreach (var unprocessedTableKeys in unprocessedKeys)
                {
                    // Print table name.
                    Console.WriteLine(unprocessedTableKeys.Key);
                    // Print unprocessed primary keys.
                    foreach (var key in unprocessedTableKeys.Value.Keys)
                    {
                        PrintItem(key);
                    }
                }

                request.RequestItems = unprocessedKeys;
            } while (response.UnprocessedKeys.Count > 0);
        }

        private static void PrintItem(Dictionary<string, AttributeValue> attributeList)
        {
            foreach (KeyValuePair<string, AttributeValue> kvp in attributeList)
            {
                string attributeName = kvp.Key;
                AttributeValue value = kvp.Value;

                Console.WriteLine(
                    attributeName + " " +
                    (value.S == null ? "" : "S=[" + value.S + "]") +
                    (value.N == null ? "" : "N=[" + value.N + "]") +
                    (value.SS == null ? "" : "SS=[" + string.Join(",", value.SS.ToArray()) + "]") +
                    (value.NS == null ? "" : "NS=[" + string.Join(",", value.NS.ToArray()) + "]")
                    );
            }
            Console.WriteLine("************************************************");
        }

        static void Main()
        {
            var client = new AmazonDynamoDBClient();

            RetrieveMultipleItemsBatchGet(client);
        }
    }
}

        /// <summary>
        /// Gets information about an existing movie from the table.
        /// </summary>
        /// <param name="client">An initialized Amazon DynamoDB client object.</param>
        /// <param name="newMovie">A Movie object containing information about
        /// the movie to retrieve.</param>
        /// <param name="tableName">The name of the table containing the movie.</param>
        /// <returns>A Dictionary object containing information about the item
        /// retrieved.</returns>
        public static async Task<Dictionary<string, AttributeValue>> GetItemAsync(AmazonDynamoDBClient client, Movie newMovie, string tableName)
        {
            var key = new Dictionary<string, AttributeValue>
            {
                ["title"] = new AttributeValue { S = newMovie.Title },
                ["year"] = new AttributeValue { N = newMovie.Year.ToString() },
            };

            var request = new GetItemRequest
            {
                Key = key,
                TableName = tableName,
            };

            var response = await client.GetItemAsync(request);
            return response.Item;
        }

    private static async Task GetTableInformation()
    {
        Console.WriteLine("\n*** Retrieving table information ***");

        var response = await Client.DescribeTableAsync(new DescribeTableRequest
        {
            TableName = ExampleTableName
        });

        var table = response.Table;
        Console.WriteLine($"Name: {table.TableName}");
        Console.WriteLine($"# of items: {table.ItemCount}");
        Console.WriteLine($"Provision Throughput (reads/sec): " +
                          $"{table.ProvisionedThroughput.ReadCapacityUnits}");
        Console.WriteLine($"Provision Throughput (writes/sec): " +
                          $"{table.ProvisionedThroughput.WriteCapacityUnits}");
    }

    private static async Task ListMyTables()
    {
        Console.WriteLine("\n*** Listing tables ***");

        string lastTableNameEvaluated = null;
        do
        {
            var response = await Client.ListTablesAsync(new ListTablesRequest
            {
                Limit = 2,
                ExclusiveStartTableName = lastTableNameEvaluated
            });

            foreach (var name in response.TableNames)
            {
                Console.WriteLine(name);
            }

            lastTableNameEvaluated = response.LastEvaluatedTableName;
        } while (lastTableNameEvaluated != null);
    }

        /// <summary>
        /// Adds a new item to the table.
        /// </summary>
        /// <param name="client">An initialized Amazon DynamoDB client object.</param>
        /// <param name="newMovie">A Movie object containing informtation for
        /// the movie to add to the table.</param>
        /// <param name="tableName">The name of the table where the item will be added.</param>
        /// <returns>A Boolean value that indicates the results of adding the item.</returns>
        public static async Task<bool> PutItemAsync(AmazonDynamoDBClient client, Movie newMovie, string tableName)
        {
            var item = new Dictionary<string, AttributeValue>
            {
                ["title"] = new AttributeValue { S = newMovie.Title },
                ["year"] = new AttributeValue { N = newMovie.Year.ToString() },
            };

            var request = new PutItemRequest
            {
                TableName = tableName,
                Item = item,
            };

            var response = await client.PutItemAsync(request);
            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }

        /// <summary>
        /// Queries the table for movies released in a particular year and
        /// then displays the information for the movies returned.
        /// </summary>
        /// <param name="client">The initialized DynamoDB client object.</param>
        /// <param name="tableName">The name of the table to query.</param>
        /// <param name="year">The release year for which we want to
        /// view movies.</param>
        /// <returns>The number of movies that match the query.</returns>
        public static async Task<int> QueryMoviesAsync(AmazonDynamoDBClient client, string tableName, int year)
        {
            var movieTable = Table.LoadTable(client, tableName);
            var filter = new QueryFilter("year", QueryOperator.Equal, year);

            Console.WriteLine("\nFind movies released in: {year}:");

            var config = new QueryOperationConfig()
            {
                Limit = 10, // 10 items per page.
                Select = SelectValues.SpecificAttributes,
                AttributesToGet = new List<string>
                {
                  "title",
                  "year",
                },
                ConsistentRead = true,
                Filter = filter,
            };

            // Value used to track how many movies match the
            // supplied criteria.
            var moviesFound = 0;

            Search search = movieTable.Query(config);
            do
            {
                var movieList = await search.GetNextSetAsync();
                moviesFound += movieList.Count;

                foreach (var movie in movieList)
                {
                    DisplayDocument(movie);
                }
            }
            while (!search.IsDone);

            return moviesFound;
        }

使用 INSERT 语句添加项目。

        /// <summary>
        /// Inserts a single movie into the movies table.
        /// </summary>
        /// <param name="tableName">The name of the table.</param>
        /// <param name="movieTitle">The title of the movie to insert.</param>
        /// <param name="year">The year that the movie was released.</param>
        /// <returns>A Boolean value that indicates the success or failure of
        /// the INSERT operation.</returns>
        public static async Task<bool> InsertSingleMovie(string tableName, string movieTitle, int year)
        {
            string insertBatch = $"INSERT INTO {tableName} VALUE {{'title': ?, 'year': ?}}";

            var response = await Client.ExecuteStatementAsync(new ExecuteStatementRequest
            {
                Statement = insertBatch,
                Parameters = new List<AttributeValue>
                {
                    new AttributeValue { S = movieTitle },
                    new AttributeValue { N = year.ToString() },
                },
            });

            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }

使用 SELECT 语句获取项目。

        /// <summary>
        /// Uses a PartiQL SELECT statement to retrieve a single movie from the
        /// movie database.
        /// </summary>
        /// <param name="tableName">The name of the movie table.</param>
        /// <param name="movieTitle">The title of the movie to retrieve.</param>
        /// <returns>A list of movie data. If no movie matches the supplied
        /// title, the list is empty.</returns>
        public static async Task<List<Dictionary<string, AttributeValue>>> GetSingleMovie(string tableName, string movieTitle)
        {
            string selectSingle = $"SELECT * FROM {tableName} WHERE title = ?";
            var parameters = new List<AttributeValue>
            {
                new AttributeValue { S = movieTitle },
            };

            var response = await Client.ExecuteStatementAsync(new ExecuteStatementRequest
            {
                Statement = selectSingle,
                Parameters = parameters,
            });

            return response.Items;
        }

使用 SELECT 语句获取项目列表。

        /// <summary>
        /// Retrieve multiple movies by year using a SELECT statement.
        /// </summary>
        /// <param name="tableName">The name of the movie table.</param>
        /// <param name="year">The year the movies were released.</param>
        /// <returns></returns>
        public static async Task<List<Dictionary<string, AttributeValue>>> GetMovies(string tableName, int year)
        {
            string selectSingle = $"SELECT * FROM {tableName} WHERE year = ?";
            var parameters = new List<AttributeValue>
            {
                new AttributeValue { N = year.ToString() },
            };

            var response = await Client.ExecuteStatementAsync(new ExecuteStatementRequest
            {
                Statement = selectSingle,
                Parameters = parameters,
            });

            return response.Items;
        }

使用 UPDATE 语句更新项目。

        /// <summary>
        /// Updates a single movie in the table, adding information for the
        /// producer.
        /// </summary>
        /// <param name="tableName">the name of the table.</param>
        /// <param name="producer">The name of the producer.</param>
        /// <param name="movieTitle">The movie title.</param>
        /// <param name="year">The year the movie was released.</param>
        /// <returns>A Boolean value that indicates the success of the
        /// UPDATE operation.</returns>
        public static async Task<bool> UpdateSingleMovie(string tableName, string producer, string movieTitle, int year)
        {
            string insertSingle = $"UPDATE {tableName} SET Producer=? WHERE title = ? AND year = ?";

            var response = await Client.ExecuteStatementAsync(new ExecuteStatementRequest
            {
                Statement = insertSingle,
                Parameters = new List<AttributeValue>
                {
                    new AttributeValue { S = producer },
                    new AttributeValue { S = movieTitle },
                    new AttributeValue { N = year.ToString() },
                },
            });

            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }

使用 DELETE 语句删除单个电影。

        /// <summary>
        /// Deletes a single movie from the table.
        /// </summary>
        /// <param name="tableName">The name of the table.</param>
        /// <param name="movieTitle">The title of the movie to delete.</param>
        /// <param name="year">The year that the movie was released.</param>
        /// <returns>A Boolean value that indicates the success of the
        /// DELETE operation.</returns>
        public static async Task<bool> DeleteSingleMovie(string tableName, string movieTitle, int year)
        {
            var deleteSingle = $"DELETE FROM {tableName} WHERE title = ? AND year = ?";

            var response = await Client.ExecuteStatementAsync(new ExecuteStatementRequest
            {
                Statement = deleteSingle,
                Parameters = new List<AttributeValue>
                {
                    new AttributeValue { S = movieTitle },
                    new AttributeValue { N = year.ToString() },
                },
            });

            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }

使用批量 INSERT 语句添加项目。

        /// <summary>
        /// Inserts movies imported from a JSON file into the movie table by
        /// using an Amazon DynamoDB PartiQL INSERT statement.
        /// </summary>
        /// <param name="tableName">The name of the table into which the movie
        /// information will be inserted.</param>
        /// <param name="movieFileName">The name of the JSON file that contains
        /// movie information.</param>
        /// <returns>A Boolean value that indicates the success or failure of
        /// the insert operation.</returns>
        public static async Task<bool> InsertMovies(string tableName, string movieFileName)
        {
            // Get the list of movies from the JSON file.
            var movies = ImportMovies(movieFileName);

            var success = false;

            if (movies is not null)
            {
                // Insert the movies in a batch using PartiQL. Because the
                // batch can contain a maximum of 25 items, insert 25 movies
                // at a time.
                string insertBatch = $"INSERT INTO {tableName} VALUE {{'title': ?, 'year': ?}}";
                var statements = new List<BatchStatementRequest>();

                try
                {
                    for (var indexOffset = 0; indexOffset < 250; indexOffset += 25)
                    {
                        for (var i = indexOffset; i < indexOffset + 25; i++)
                        {
                            statements.Add(new BatchStatementRequest
                            {
                                Statement = insertBatch,
                                Parameters = new List<AttributeValue>
                                {
                                    new AttributeValue { S = movies[i].Title },
                                    new AttributeValue { N = movies[i].Year.ToString() },
                                },
                            });
                        }

                        var response = await Client.BatchExecuteStatementAsync(new BatchExecuteStatementRequest
                        {
                            Statements = statements,
                        });

                        // Wait between batches for movies to be successfully added.
                        System.Threading.Thread.Sleep(3000);

                        success = response.HttpStatusCode == System.Net.HttpStatusCode.OK;

                        // Clear the list of statements for the next batch.
                        statements.Clear();
                    }
                }
                catch (AmazonDynamoDBException ex)
                {
                    Console.WriteLine(ex.Message);
                }
            }

            return success;
        }

        /// <summary>
        /// Loads the contents of a JSON file into a list of movies to be
        /// added to the DynamoDB table.
        /// </summary>
        /// <param name="movieFileName">The full path to the JSON file.</param>
        /// <returns>A generic list of movie objects.</returns>
        public static List<Movie> ImportMovies(string movieFileName)
        {
            if (!File.Exists(movieFileName))
            {
                return null!;
            }

            using var sr = new StreamReader(movieFileName);
            string json = sr.ReadToEnd();
            var allMovies = JsonConvert.DeserializeObject<List<Movie>>(json);

            if (allMovies is not null)
            {
                // Return the first 250 entries.
                return allMovies.GetRange(0, 250);
            }
            else
            {
                return null!;
            }
        }

使用批量 SELECT 语句获取项目。

        /// <summary>
        /// Gets movies from the movie table by
        /// using an Amazon DynamoDB PartiQL SELECT statement.
        /// </summary>
        /// <param name="tableName">The name of the table.</param>
        /// <param name="title1">The title of the first movie.</param>
        /// <param name="title2">The title of the second movie.</param>
        /// <param name="year1">The year of the first movie.</param>
        /// <param name="year2">The year of the second movie.</param>
        /// <returns>True if successful.</returns>
        public static async Task<bool> GetBatch(
            string tableName,
            string title1,
            string title2,
            int year1,
            int year2)
        {
            var getBatch = $"SELECT FROM {tableName} WHERE title = ? AND year = ?";
            var statements = new List<BatchStatementRequest>
            {
                new BatchStatementRequest
                {
                    Statement = getBatch,
                    Parameters = new List<AttributeValue>
                    {
                        new AttributeValue { S = title1 },
                        new AttributeValue { N = year1.ToString() },
                    },
                },

                new BatchStatementRequest
                {
                    Statement = getBatch,
                    Parameters = new List<AttributeValue>
                    {
                        new AttributeValue { S = title2 },
                        new AttributeValue { N = year2.ToString() },
                    },
                }
            };

            var response = await Client.BatchExecuteStatementAsync(new BatchExecuteStatementRequest
            {
                Statements = statements,
            });

            if (response.Responses.Count > 0)
            {
                response.Responses.ForEach(r =>
                {
                    Console.WriteLine($"{r.Item["title"]}\t{r.Item["year"]}");
                });
                return true;
            }
            else
            {
                Console.WriteLine($"Couldn't find either {title1} or {title2}.");
                return false;
            }

        }

使用批量 UPDATE 语句更新项目。

        /// <summary>
        /// Updates information for multiple movies.
        /// </summary>
        /// <param name="tableName">The name of the table containing the
        /// movies to be updated.</param>
        /// <param name="producer1">The producer name for the first movie
        /// to update.</param>
        /// <param name="title1">The title of the first movie.</param>
        /// <param name="year1">The year that the first movie was released.</param>
        /// <param name="producer2">The producer name for the second
        /// movie to update.</param>
        /// <param name="title2">The title of the second movie.</param>
        /// <param name="year2">The year that the second movie was released.</param>
        /// <returns>A Boolean value that indicates the success of the update.</returns>
        public static async Task<bool> UpdateBatch(
            string tableName,
            string producer1,
            string title1,
            int year1,
            string producer2,
            string title2,
            int year2)
        {

            string updateBatch = $"UPDATE {tableName} SET Producer=? WHERE title = ? AND year = ?";
            var statements = new List<BatchStatementRequest>
            {
                new BatchStatementRequest
                {
                    Statement = updateBatch,
                    Parameters = new List<AttributeValue>
                    {
                        new AttributeValue { S = producer1 },
                        new AttributeValue { S = title1 },
                        new AttributeValue { N = year1.ToString() },
                    },
                },

                new BatchStatementRequest
                {
                    Statement = updateBatch,
                    Parameters = new List<AttributeValue>
                    {
                        new AttributeValue { S = producer2 },
                        new AttributeValue { S = title2 },
                        new AttributeValue { N = year2.ToString() },
                    },
                }
            };

            var response = await Client.BatchExecuteStatementAsync(new BatchExecuteStatementRequest
            {
                Statements = statements,
            });

            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }

使用批量 DELETE 语句删除项目。

        /// <summary>
        /// Deletes multiple movies using a PartiQL BatchExecuteAsync
        /// statement.
        /// </summary>
        /// <param name="tableName">The name of the table containing the
        /// moves that will be deleted.</param>
        /// <param name="title1">The title of the first movie.</param>
        /// <param name="year1">The year the first movie was released.</param>
        /// <param name="title2">The title of the second movie.</param>
        /// <param name="year2">The year the second movie was released.</param>
        /// <returns>A Boolean value indicating the success of the operation.</returns>
        public static async Task<bool> DeleteBatch(
            string tableName,
            string title1,
            int year1,
            string title2,
            int year2)
        {

            string updateBatch = $"DELETE FROM {tableName} WHERE title = ? AND year = ?";
            var statements = new List<BatchStatementRequest>
            {
                new BatchStatementRequest
                {
                    Statement = updateBatch,
                    Parameters = new List<AttributeValue>
                    {
                        new AttributeValue { S = title1 },
                        new AttributeValue { N = year1.ToString() },
                    },
                },

                new BatchStatementRequest
                {
                    Statement = updateBatch,
                    Parameters = new List<AttributeValue>
                    {
                        new AttributeValue { S = title2 },
                        new AttributeValue { N = year2.ToString() },
                    },
                }
            };

            var response = await Client.BatchExecuteStatementAsync(new BatchExecuteStatementRequest
            {
                Statements = statements,
            });

            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }

        public static async Task<int> ScanTableAsync(
            AmazonDynamoDBClient client,
            string tableName,
            int startYear,
            int endYear)
        {
            var request = new ScanRequest
            {
                TableName = tableName,
                ExpressionAttributeNames = new Dictionary<string, string>
                {
                  { "#yr", "year" },
                },
                ExpressionAttributeValues = new Dictionary<string, AttributeValue>
                {
                    { ":y_a", new AttributeValue { N = startYear.ToString() } },
                    { ":y_z", new AttributeValue { N = endYear.ToString() } },
                },
                FilterExpression = "#yr between :y_a and :y_z",
                ProjectionExpression = "#yr, title, info.actors[0], info.directors, info.running_time_secs",
                Limit = 10 // Set a limit to demonstrate using the LastEvaluatedKey.
            };

            // Keep track of how many movies were found.
            int foundCount = 0;

            var response = new ScanResponse();
            do
            {
                response = await client.ScanAsync(request);
                foundCount += response.Items.Count;
                response.Items.ForEach(i => DisplayItem(i));
                request.ExclusiveStartKey = response.LastEvaluatedKey;
            }
            while (response.LastEvaluatedKey.Count > 0);
            return foundCount;
        }

        /// <summary>
        /// Updates an existing item in the movies table.
        /// </summary>
        /// <param name="client">An initialized Amazon DynamoDB client object.</param>
        /// <param name="newMovie">A Movie object containing information for
        /// the movie to update.</param>
        /// <param name="newInfo">A MovieInfo object that contains the
        /// information that will be changed.</param>
        /// <param name="tableName">The name of the table that contains the movie.</param>
        /// <returns>A Boolean value that indicates the success of the operation.</returns>
        public static async Task<bool> UpdateItemAsync(
            AmazonDynamoDBClient client,
            Movie newMovie,
            MovieInfo newInfo,
            string tableName)
        {
            var key = new Dictionary<string, AttributeValue>
            {
                ["title"] = new AttributeValue { S = newMovie.Title },
                ["year"] = new AttributeValue { N = newMovie.Year.ToString() },
            };
            var updates = new Dictionary<string, AttributeValueUpdate>
            {
                ["info.plot"] = new AttributeValueUpdate
                {
                    Action = AttributeAction.PUT,
                    Value = new AttributeValue { S = newInfo.Plot },
                },

                ["info.rating"] = new AttributeValueUpdate
                {
                    Action = AttributeAction.PUT,
                    Value = new AttributeValue { N = newInfo.Rank.ToString() },
                },
            };

            var request = new UpdateItemRequest
            {
                AttributeUpdates = updates,
                Key = key,
                TableName = tableName,
            };

            var response = await client.UpdateItemAsync(request);

            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }

将一批项目写入影片表。

        /// <summary>
        /// Loads the contents of a JSON file into a list of movies to be
        /// added to the DynamoDB table.
        /// </summary>
        /// <param name="movieFileName">The full path to the JSON file.</param>
        /// <returns>A generic list of movie objects.</returns>
        public static List<Movie> ImportMovies(string movieFileName)
        {
            if (!File.Exists(movieFileName))
            {
                return null;
            }

            using var sr = new StreamReader(movieFileName);
            string json = sr.ReadToEnd();
            var allMovies = JsonSerializer.Deserialize<List<Movie>>(
                json,
                new JsonSerializerOptions
                {
                    PropertyNameCaseInsensitive = true
                });

            // Now return the first 250 entries.
            return allMovies.GetRange(0, 250);
        }

        /// <summary>
        /// Writes 250 items to the movie table.
        /// </summary>
        /// <param name="client">The initialized DynamoDB client object.</param>
        /// <param name="movieFileName">A string containing the full path to
        /// the JSON file containing movie data.</param>
        /// <returns>A long integer value representing the number of movies
        /// imported from the JSON file.</returns>
        public static async Task<long> BatchWriteItemsAsync(
            AmazonDynamoDBClient client,
            string movieFileName)
        {
            var movies = ImportMovies(movieFileName);
            if (movies is null)
            {
                Console.WriteLine("Couldn't find the JSON file with movie data.");
                return 0;
            }

            var context = new DynamoDBContext(client);

            var movieBatch = context.CreateBatchWrite<Movie>();
            movieBatch.AddPutItems(movies);

            Console.WriteLine("Adding imported movies to the table.");
            await movieBatch.ExecuteAsync();

            return movies.Count;
        }

// This example application performs the following basic Amazon DynamoDB
// functions:
//
//     CreateTableAsync
//     PutItemAsync
//     UpdateItemAsync
//     BatchWriteItemAsync
//     GetItemAsync
//     DeleteItemAsync
//     Query
//     Scan
//     DeleteItemAsync
//
using Amazon.DynamoDBv2;
using DynamoDB_Actions;

public class DynamoDB_Basics
{
    // Separator for the console display.
    private static readonly string SepBar = new string('-', 80);

    public static async Task Main()
    {
        var client = new AmazonDynamoDBClient();

        var tableName = "movie_table";

        // Relative path to moviedata.json in the local repository.
        var movieFileName = @"..\..\..\..\..\..\..\..\resources\sample_files\movies.json";

        DisplayInstructions();

        // Create a new table and wait for it to be active.
        Console.WriteLine($"Creating the new table: {tableName}");

        var success = await DynamoDbMethods.CreateMovieTableAsync(client, tableName);

        if (success)
        {
            Console.WriteLine($"\nTable: {tableName} successfully created.");
        }
        else
        {
            Console.WriteLine($"\nCould not create {tableName}.");
        }

        WaitForEnter();

        // Add a single new movie to the table.
        var newMovie = new Movie
        {
            Year = 2021,
            Title = "Spider-Man: No Way Home",
        };

        success = await DynamoDbMethods.PutItemAsync(client, newMovie, tableName);
        if (success)
        {
            Console.WriteLine($"Added {newMovie.Title} to the table.");
        }
        else
        {
            Console.WriteLine("Could not add movie to table.");
        }

        WaitForEnter();

        // Update the new movie by adding a plot and rank.
        var newInfo = new MovieInfo
        {
            Plot = "With Spider-Man's identity now revealed, Peter asks" +
                   "Doctor Strange for help. When a spell goes wrong, dangerous" +
                   "foes from other worlds start to appear, forcing Peter to" +
                   "discover what it truly means to be Spider-Man.",
            Rank = 9,
        };

        success = await DynamoDbMethods.UpdateItemAsync(client, newMovie, newInfo, tableName);
        if (success)
        {
            Console.WriteLine($"Successfully updated the movie: {newMovie.Title}");
        }
        else
        {
            Console.WriteLine("Could not update the movie.");
        }

        WaitForEnter();

        // Add a batch of movies to the DynamoDB table from a list of
        // movies in a JSON file.
        var itemCount = await DynamoDbMethods.BatchWriteItemsAsync(client, movieFileName);
        Console.WriteLine($"Added {itemCount} movies to the table.");

        WaitForEnter();

        // Get a movie by key. (partition + sort)
        var lookupMovie = new Movie
        {
            Title = "Jurassic Park",
            Year = 1993,
        };

        Console.WriteLine("Looking for the movie \"Jurassic Park\".");
        var item = await DynamoDbMethods.GetItemAsync(client, lookupMovie, tableName);
        if (item.Count > 0)
        {
            DynamoDbMethods.DisplayItem(item);
        }
        else
        {
            Console.WriteLine($"Couldn't find {lookupMovie.Title}");
        }

        WaitForEnter();

        // Delete a movie.
        var movieToDelete = new Movie
        {
            Title = "The Town",
            Year = 2010,
        };

        success = await DynamoDbMethods.DeleteItemAsync(client, tableName, movieToDelete);

        if (success)
        {
            Console.WriteLine($"Successfully deleted {movieToDelete.Title}.");
        }
        else
        {
            Console.WriteLine($"Could not delete {movieToDelete.Title}.");
        }

        WaitForEnter();

        // Use Query to find all the movies released in 2010.
        int findYear = 2010;
        Console.WriteLine($"Movies released in {findYear}");
        var queryCount = await DynamoDbMethods.QueryMoviesAsync(client, tableName, findYear);
        Console.WriteLine($"Found {queryCount} movies released in {findYear}");

        WaitForEnter();

        // Use Scan to get a list of movies from 2001 to 2011.
        int startYear = 2001;
        int endYear = 2011;
        var scanCount = await DynamoDbMethods.ScanTableAsync(client, tableName, startYear, endYear);
        Console.WriteLine($"Found {scanCount} movies released between {startYear} and {endYear}");

        WaitForEnter();

        // Delete the table.
        success = await DynamoDbMethods.DeleteTableAsync(client, tableName);

        if (success)
        {
            Console.WriteLine($"Successfully deleted {tableName}");
        }
        else
        {
            Console.WriteLine($"Could not delete {tableName}");
        }

        Console.WriteLine("The DynamoDB Basics example application is done.");

        WaitForEnter();
    }

    /// <summary>
    /// Displays the description of the application on the console.
    /// </summary>
    private static void DisplayInstructions()
    {
        Console.Clear();
        Console.WriteLine();
        Console.Write(new string(' ', 28));
        Console.WriteLine("DynamoDB Basics Example");
        Console.WriteLine(SepBar);
        Console.WriteLine("This demo application shows the basics of using DynamoDB with the AWS SDK.");
        Console.WriteLine(SepBar);
        Console.WriteLine("The application does the following:");
        Console.WriteLine("\t1. Creates a table with partition: year and sort:title.");
        Console.WriteLine("\t2. Adds a single movie to the table.");
        Console.WriteLine("\t3. Adds movies to the table from moviedata.json.");
        Console.WriteLine("\t4. Updates the rating and plot of the movie that was just added.");
        Console.WriteLine("\t5. Gets a movie using its key (partition + sort).");
        Console.WriteLine("\t6. Deletes a movie.");
        Console.WriteLine("\t7. Uses QueryAsync to return all movies released in a given year.");
        Console.WriteLine("\t8. Uses ScanAsync to return all movies released within a range of years.");
        Console.WriteLine("\t9. Finally, it deletes the table that was just created.");
        WaitForEnter();
    }

    /// <summary>
    /// Simple method to wait for the Enter key to be pressed.
    /// </summary>
    private static void WaitForEnter()
    {
        Console.WriteLine("\nPress <Enter> to continue.");
        Console.WriteLine(SepBar);
        _ = Console.ReadLine();
    }
}

创建一个包含影片数据的表。

        /// <summary>
        /// Creates a new Amazon DynamoDB table and then waits for the new
        /// table to become active.
        /// </summary>
        /// <param name="client">An initialized Amazon DynamoDB client object.</param>
        /// <param name="tableName">The name of the table to create.</param>
        /// <returns>A Boolean value indicating the success of the operation.</returns>
        public static async Task<bool> CreateMovieTableAsync(AmazonDynamoDBClient client, string tableName)
        {
            var response = await client.CreateTableAsync(new CreateTableRequest
            {
                TableName = tableName,
                AttributeDefinitions = new List<AttributeDefinition>()
                {
                    new AttributeDefinition
                    {
                        AttributeName = "title",
                        AttributeType = ScalarAttributeType.S,
                    },
                    new AttributeDefinition
                    {
                        AttributeName = "year",
                        AttributeType = ScalarAttributeType.N,
                    },
                },
                KeySchema = new List<KeySchemaElement>()
                {
                    new KeySchemaElement
                    {
                        AttributeName = "year",
                        KeyType = KeyType.HASH,
                    },
                    new KeySchemaElement
                    {
                        AttributeName = "title",
                        KeyType = KeyType.RANGE,
                    },
                },
                ProvisionedThroughput = new ProvisionedThroughput
                {
                    ReadCapacityUnits = 5,
                    WriteCapacityUnits = 5,
                },
            });

            // Wait until the table is ACTIVE and then report success.
            Console.Write("Waiting for table to become active...");

            var request = new DescribeTableRequest
            {
                TableName = response.TableDescription.TableName,
            };

            TableStatus status;

            int sleepDuration = 2000;

            do
            {
                System.Threading.Thread.Sleep(sleepDuration);

                var describeTableResponse = await client.DescribeTableAsync(request);
                status = describeTableResponse.Table.TableStatus;

                Console.Write(".");
            }
            while (status != "ACTIVE");

            return status == TableStatus.ACTIVE;
        }

将单个影片添加到表中。

        /// <summary>
        /// Adds a new item to the table.
        /// </summary>
        /// <param name="client">An initialized Amazon DynamoDB client object.</param>
        /// <param name="newMovie">A Movie object containing informtation for
        /// the movie to add to the table.</param>
        /// <param name="tableName">The name of the table where the item will be added.</param>
        /// <returns>A Boolean value that indicates the results of adding the item.</returns>
        public static async Task<bool> PutItemAsync(AmazonDynamoDBClient client, Movie newMovie, string tableName)
        {
            var item = new Dictionary<string, AttributeValue>
            {
                ["title"] = new AttributeValue { S = newMovie.Title },
                ["year"] = new AttributeValue { N = newMovie.Year.ToString() },
            };

            var request = new PutItemRequest
            {
                TableName = tableName,
                Item = item,
            };

            var response = await client.PutItemAsync(request);
            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }

更新表中的单个项目。

        /// <summary>
        /// Updates an existing item in the movies table.
        /// </summary>
        /// <param name="client">An initialized Amazon DynamoDB client object.</param>
        /// <param name="newMovie">A Movie object containing information for
        /// the movie to update.</param>
        /// <param name="newInfo">A MovieInfo object that contains the
        /// information that will be changed.</param>
        /// <param name="tableName">The name of the table that contains the movie.</param>
        /// <returns>A Boolean value that indicates the success of the operation.</returns>
        public static async Task<bool> UpdateItemAsync(
            AmazonDynamoDBClient client,
            Movie newMovie,
            MovieInfo newInfo,
            string tableName)
        {
            var key = new Dictionary<string, AttributeValue>
            {
                ["title"] = new AttributeValue { S = newMovie.Title },
                ["year"] = new AttributeValue { N = newMovie.Year.ToString() },
            };
            var updates = new Dictionary<string, AttributeValueUpdate>
            {
                ["info.plot"] = new AttributeValueUpdate
                {
                    Action = AttributeAction.PUT,
                    Value = new AttributeValue { S = newInfo.Plot },
                },

                ["info.rating"] = new AttributeValueUpdate
                {
                    Action = AttributeAction.PUT,
                    Value = new AttributeValue { N = newInfo.Rank.ToString() },
                },
            };

            var request = new UpdateItemRequest
            {
                AttributeUpdates = updates,
                Key = key,
                TableName = tableName,
            };

            var response = await client.UpdateItemAsync(request);

            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }

从影片表中检索单个项目。

        /// <summary>
        /// Gets information about an existing movie from the table.
        /// </summary>
        /// <param name="client">An initialized Amazon DynamoDB client object.</param>
        /// <param name="newMovie">A Movie object containing information about
        /// the movie to retrieve.</param>
        /// <param name="tableName">The name of the table containing the movie.</param>
        /// <returns>A Dictionary object containing information about the item
        /// retrieved.</returns>
        public static async Task<Dictionary<string, AttributeValue>> GetItemAsync(AmazonDynamoDBClient client, Movie newMovie, string tableName)
        {
            var key = new Dictionary<string, AttributeValue>
            {
                ["title"] = new AttributeValue { S = newMovie.Title },
                ["year"] = new AttributeValue { N = newMovie.Year.ToString() },
            };

            var request = new GetItemRequest
            {
                Key = key,
                TableName = tableName,
            };

            var response = await client.GetItemAsync(request);
            return response.Item;
        }

将一批项目写入影片表。

        /// <summary>
        /// Loads the contents of a JSON file into a list of movies to be
        /// added to the DynamoDB table.
        /// </summary>
        /// <param name="movieFileName">The full path to the JSON file.</param>
        /// <returns>A generic list of movie objects.</returns>
        public static List<Movie> ImportMovies(string movieFileName)
        {
            if (!File.Exists(movieFileName))
            {
                return null;
            }

            using var sr = new StreamReader(movieFileName);
            string json = sr.ReadToEnd();
            var allMovies = JsonSerializer.Deserialize<List<Movie>>(
                json,
                new JsonSerializerOptions
                {
                    PropertyNameCaseInsensitive = true
                });

            // Now return the first 250 entries.
            return allMovies.GetRange(0, 250);
        }

        /// <summary>
        /// Writes 250 items to the movie table.
        /// </summary>
        /// <param name="client">The initialized DynamoDB client object.</param>
        /// <param name="movieFileName">A string containing the full path to
        /// the JSON file containing movie data.</param>
        /// <returns>A long integer value representing the number of movies
        /// imported from the JSON file.</returns>
        public static async Task<long> BatchWriteItemsAsync(
            AmazonDynamoDBClient client,
            string movieFileName)
        {
            var movies = ImportMovies(movieFileName);
            if (movies is null)
            {
                Console.WriteLine("Couldn't find the JSON file with movie data.");
                return 0;
            }

            var context = new DynamoDBContext(client);

            var movieBatch = context.CreateBatchWrite<Movie>();
            movieBatch.AddPutItems(movies);

            Console.WriteLine("Adding imported movies to the table.");
            await movieBatch.ExecuteAsync();

            return movies.Count;
        }

从表中删除单个项目。

        /// <summary>
        /// Deletes a single item from a DynamoDB table.
        /// </summary>
        /// <param name="client">The initialized DynamoDB client object.</param>
        /// <param name="tableName">The name of the table from which the item
        /// will be deleted.</param>
        /// <param name="movieToDelete">A movie object containing the title and
        /// year of the movie to delete.</param>
        /// <returns>A Boolean value indicating the success or failure of the
        /// delete operation.</returns>
        public static async Task<bool> DeleteItemAsync(
            AmazonDynamoDBClient client,
            string tableName,
            Movie movieToDelete)
        {
            var key = new Dictionary<string, AttributeValue>
            {
                ["title"] = new AttributeValue { S = movieToDelete.Title },
                ["year"] = new AttributeValue { N = movieToDelete.Year.ToString() },
            };

            var request = new DeleteItemRequest
            {
                TableName = tableName,
                Key = key,
            };

            var response = await client.DeleteItemAsync(request);
            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }

查询表中是否有特定年份发行的影片。

        /// <summary>
        /// Queries the table for movies released in a particular year and
        /// then displays the information for the movies returned.
        /// </summary>
        /// <param name="client">The initialized DynamoDB client object.</param>
        /// <param name="tableName">The name of the table to query.</param>
        /// <param name="year">The release year for which we want to
        /// view movies.</param>
        /// <returns>The number of movies that match the query.</returns>
        public static async Task<int> QueryMoviesAsync(AmazonDynamoDBClient client, string tableName, int year)
        {
            var movieTable = Table.LoadTable(client, tableName);
            var filter = new QueryFilter("year", QueryOperator.Equal, year);

            Console.WriteLine("\nFind movies released in: {year}:");

            var config = new QueryOperationConfig()
            {
                Limit = 10, // 10 items per page.
                Select = SelectValues.SpecificAttributes,
                AttributesToGet = new List<string>
                {
                  "title",
                  "year",
                },
                ConsistentRead = true,
                Filter = filter,
            };

            // Value used to track how many movies match the
            // supplied criteria.
            var moviesFound = 0;

            Search search = movieTable.Query(config);
            do
            {
                var movieList = await search.GetNextSetAsync();
                moviesFound += movieList.Count;

                foreach (var movie in movieList)
                {
                    DisplayDocument(movie);
                }
            }
            while (!search.IsDone);

            return moviesFound;
        }

扫描此表以查找几年内发行的影片。

        public static async Task<int> ScanTableAsync(
            AmazonDynamoDBClient client,
            string tableName,
            int startYear,
            int endYear)
        {
            var request = new ScanRequest
            {
                TableName = tableName,
                ExpressionAttributeNames = new Dictionary<string, string>
                {
                  { "#yr", "year" },
                },
                ExpressionAttributeValues = new Dictionary<string, AttributeValue>
                {
                    { ":y_a", new AttributeValue { N = startYear.ToString() } },
                    { ":y_z", new AttributeValue { N = endYear.ToString() } },
                },
                FilterExpression = "#yr between :y_a and :y_z",
                ProjectionExpression = "#yr, title, info.actors[0], info.directors, info.running_time_secs",
                Limit = 10 // Set a limit to demonstrate using the LastEvaluatedKey.
            };

            // Keep track of how many movies were found.
            int foundCount = 0;

            var response = new ScanResponse();
            do
            {
                response = await client.ScanAsync(request);
                foundCount += response.Items.Count;
                response.Items.ForEach(i => DisplayItem(i));
                request.ExclusiveStartKey = response.LastEvaluatedKey;
            }
            while (response.LastEvaluatedKey.Count > 0);
            return foundCount;
        }

删除影片表。

        public static async Task<bool> DeleteTableAsync(AmazonDynamoDBClient client, string tableName)
        {
            var request = new DeleteTableRequest
            {
                TableName = tableName,
            };

            var response = await client.DeleteTableAsync(request);
            if (response.HttpStatusCode == System.Net.HttpStatusCode.OK)
            {
                Console.WriteLine($"Table {response.TableDescription.TableName} successfully deleted.");
                return true;
            }
            else
            {
                Console.WriteLine("Could not delete table.");
                return false;
            }
        }

// Before you run this example, download 'movies.json' from
// https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/GettingStarted.Js.02.html,
// and put it in the same folder as the example.

// Separator for the console display.
var SepBar = new string('-', 80);
const string tableName = "movie_table";
const string movieFileName = "moviedata.json";

DisplayInstructions();

// Create the table and wait for it to be active.
Console.WriteLine($"Creating the movie table: {tableName}");

var success = await DynamoDBMethods.CreateMovieTableAsync(tableName);
if (success)
{
    Console.WriteLine($"Successfully created table: {tableName}.");
}

WaitForEnter();

// Add movie information to the table from moviedata.json. See the
// instructions at the top of this file to download the JSON file.
Console.WriteLine($"Inserting movies into the new table. Please wait...");
success = await PartiQLBatchMethods.InsertMovies(tableName, movieFileName);
if (success)
{
    Console.WriteLine("Movies successfully added to the table.");
}
else
{
    Console.WriteLine("Movies could not be added to the table.");
}

WaitForEnter();

// Update multiple movies by using the BatchExecute statement.
var title1 = "Star Wars";
var year1 = 1977;
var title2 = "Wizard of Oz";
var year2 = 1939;

Console.WriteLine($"Updating two movies with producer information: {title1} and {title2}.");
success = await PartiQLBatchMethods.GetBatch(tableName, title1, title2, year1, year2);
if (success)
{
    Console.WriteLine($"Successfully retrieved {title1} and {title2}.");
}
else
{
    Console.WriteLine("Select statement failed.");
}

WaitForEnter();

// Update multiple movies by using the BatchExecute statement.
var producer1 = "LucasFilm";
var producer2 = "MGM";

Console.WriteLine($"Updating two movies with producer information: {title1} and {title2}.");
success = await PartiQLBatchMethods.UpdateBatch(tableName, producer1, title1, year1, producer2, title2, year2);
if (success)
{
    Console.WriteLine($"Successfully updated {title1} and {title2}.");
}
else
{
    Console.WriteLine("Update failed.");
}

WaitForEnter();

// Delete multiple movies by using the BatchExecute statement.
Console.WriteLine($"Now we will delete {title1} and {title2} from the table.");
success = await PartiQLBatchMethods.DeleteBatch(tableName, title1, year1, title2, year2);

if (success)
{
    Console.WriteLine($"Deleted {title1} and {title2}");
}
else
{
    Console.WriteLine($"could not delete {title1} or {title2}");
}

WaitForEnter();

// DNow that the PartiQL Batch scenario is complete, delete the movie table.
success = await DynamoDBMethods.DeleteTableAsync(tableName);

if (success)
{
    Console.WriteLine($"Successfully deleted {tableName}");
}
else
{
    Console.WriteLine($"Could not delete {tableName}");
}

/// <summary>
/// Displays the description of the application on the console.
/// </summary>
void DisplayInstructions()
{
    Console.Clear();
    Console.WriteLine();
    Console.Write(new string(' ', 24));
    Console.WriteLine("DynamoDB PartiQL Basics Example");
    Console.WriteLine(SepBar);
    Console.WriteLine("This demo application shows the basics of using Amazon DynamoDB with the AWS SDK for");
    Console.WriteLine(".NET version 3.7 and .NET 6.");
    Console.WriteLine(SepBar);
    Console.WriteLine("Creates a table by using the CreateTable method.");
    Console.WriteLine("Gets multiple movies by using a PartiQL SELECT statement.");
    Console.WriteLine("Updates multiple movies by using the ExecuteBatch method.");
    Console.WriteLine("Deletes multiple movies by using a PartiQL DELETE statement.");
    Console.WriteLine("Cleans up the resources created for the demo by deleting the table.");
    Console.WriteLine(SepBar);

    WaitForEnter();
}

/// <summary>
/// Simple method to wait for the <Enter> key to be pressed.
/// </summary>
void WaitForEnter()
{
    Console.WriteLine("\nPress <Enter> to continue.");
    Console.Write(SepBar);
    _ = Console.ReadLine();
}


        /// <summary>
        /// Gets movies from the movie table by
        /// using an Amazon DynamoDB PartiQL SELECT statement.
        /// </summary>
        /// <param name="tableName">The name of the table.</param>
        /// <param name="title1">The title of the first movie.</param>
        /// <param name="title2">The title of the second movie.</param>
        /// <param name="year1">The year of the first movie.</param>
        /// <param name="year2">The year of the second movie.</param>
        /// <returns>True if successful.</returns>
        public static async Task<bool> GetBatch(
            string tableName,
            string title1,
            string title2,
            int year1,
            int year2)
        {
            var getBatch = $"SELECT FROM {tableName} WHERE title = ? AND year = ?";
            var statements = new List<BatchStatementRequest>
            {
                new BatchStatementRequest
                {
                    Statement = getBatch,
                    Parameters = new List<AttributeValue>
                    {
                        new AttributeValue { S = title1 },
                        new AttributeValue { N = year1.ToString() },
                    },
                },

                new BatchStatementRequest
                {
                    Statement = getBatch,
                    Parameters = new List<AttributeValue>
                    {
                        new AttributeValue { S = title2 },
                        new AttributeValue { N = year2.ToString() },
                    },
                }
            };

            var response = await Client.BatchExecuteStatementAsync(new BatchExecuteStatementRequest
            {
                Statements = statements,
            });

            if (response.Responses.Count > 0)
            {
                response.Responses.ForEach(r =>
                {
                    Console.WriteLine($"{r.Item["title"]}\t{r.Item["year"]}");
                });
                return true;
            }
            else
            {
                Console.WriteLine($"Couldn't find either {title1} or {title2}.");
                return false;
            }

        }

        /// <summary>
        /// Inserts movies imported from a JSON file into the movie table by
        /// using an Amazon DynamoDB PartiQL INSERT statement.
        /// </summary>
        /// <param name="tableName">The name of the table into which the movie
        /// information will be inserted.</param>
        /// <param name="movieFileName">The name of the JSON file that contains
        /// movie information.</param>
        /// <returns>A Boolean value that indicates the success or failure of
        /// the insert operation.</returns>
        public static async Task<bool> InsertMovies(string tableName, string movieFileName)
        {
            // Get the list of movies from the JSON file.
            var movies = ImportMovies(movieFileName);

            var success = false;

            if (movies is not null)
            {
                // Insert the movies in a batch using PartiQL. Because the
                // batch can contain a maximum of 25 items, insert 25 movies
                // at a time.
                string insertBatch = $"INSERT INTO {tableName} VALUE {{'title': ?, 'year': ?}}";
                var statements = new List<BatchStatementRequest>();

                try
                {
                    for (var indexOffset = 0; indexOffset < 250; indexOffset += 25)
                    {
                        for (var i = indexOffset; i < indexOffset + 25; i++)
                        {
                            statements.Add(new BatchStatementRequest
                            {
                                Statement = insertBatch,
                                Parameters = new List<AttributeValue>
                                {
                                    new AttributeValue { S = movies[i].Title },
                                    new AttributeValue { N = movies[i].Year.ToString() },
                                },
                            });
                        }

                        var response = await Client.BatchExecuteStatementAsync(new BatchExecuteStatementRequest
                        {
                            Statements = statements,
                        });

                        // Wait between batches for movies to be successfully added.
                        System.Threading.Thread.Sleep(3000);

                        success = response.HttpStatusCode == System.Net.HttpStatusCode.OK;

                        // Clear the list of statements for the next batch.
                        statements.Clear();
                    }
                }
                catch (AmazonDynamoDBException ex)
                {
                    Console.WriteLine(ex.Message);
                }
            }

            return success;
        }

        /// <summary>
        /// Loads the contents of a JSON file into a list of movies to be
        /// added to the DynamoDB table.
        /// </summary>
        /// <param name="movieFileName">The full path to the JSON file.</param>
        /// <returns>A generic list of movie objects.</returns>
        public static List<Movie> ImportMovies(string movieFileName)
        {
            if (!File.Exists(movieFileName))
            {
                return null!;
            }

            using var sr = new StreamReader(movieFileName);
            string json = sr.ReadToEnd();
            var allMovies = JsonConvert.DeserializeObject<List<Movie>>(json);

            if (allMovies is not null)
            {
                // Return the first 250 entries.
                return allMovies.GetRange(0, 250);
            }
            else
            {
                return null!;
            }
        }

        /// <summary>
        /// Updates information for multiple movies.
        /// </summary>
        /// <param name="tableName">The name of the table containing the
        /// movies to be updated.</param>
        /// <param name="producer1">The producer name for the first movie
        /// to update.</param>
        /// <param name="title1">The title of the first movie.</param>
        /// <param name="year1">The year that the first movie was released.</param>
        /// <param name="producer2">The producer name for the second
        /// movie to update.</param>
        /// <param name="title2">The title of the second movie.</param>
        /// <param name="year2">The year that the second movie was released.</param>
        /// <returns>A Boolean value that indicates the success of the update.</returns>
        public static async Task<bool> UpdateBatch(
            string tableName,
            string producer1,
            string title1,
            int year1,
            string producer2,
            string title2,
            int year2)
        {

            string updateBatch = $"UPDATE {tableName} SET Producer=? WHERE title = ? AND year = ?";
            var statements = new List<BatchStatementRequest>
            {
                new BatchStatementRequest
                {
                    Statement = updateBatch,
                    Parameters = new List<AttributeValue>
                    {
                        new AttributeValue { S = producer1 },
                        new AttributeValue { S = title1 },
                        new AttributeValue { N = year1.ToString() },
                    },
                },

                new BatchStatementRequest
                {
                    Statement = updateBatch,
                    Parameters = new List<AttributeValue>
                    {
                        new AttributeValue { S = producer2 },
                        new AttributeValue { S = title2 },
                        new AttributeValue { N = year2.ToString() },
                    },
                }
            };

            var response = await Client.BatchExecuteStatementAsync(new BatchExecuteStatementRequest
            {
                Statements = statements,
            });

            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }

        /// <summary>
        /// Deletes multiple movies using a PartiQL BatchExecuteAsync
        /// statement.
        /// </summary>
        /// <param name="tableName">The name of the table containing the
        /// moves that will be deleted.</param>
        /// <param name="title1">The title of the first movie.</param>
        /// <param name="year1">The year the first movie was released.</param>
        /// <param name="title2">The title of the second movie.</param>
        /// <param name="year2">The year the second movie was released.</param>
        /// <returns>A Boolean value indicating the success of the operation.</returns>
        public static async Task<bool> DeleteBatch(
            string tableName,
            string title1,
            int year1,
            string title2,
            int year2)
        {

            string updateBatch = $"DELETE FROM {tableName} WHERE title = ? AND year = ?";
            var statements = new List<BatchStatementRequest>
            {
                new BatchStatementRequest
                {
                    Statement = updateBatch,
                    Parameters = new List<AttributeValue>
                    {
                        new AttributeValue { S = title1 },
                        new AttributeValue { N = year1.ToString() },
                    },
                },

                new BatchStatementRequest
                {
                    Statement = updateBatch,
                    Parameters = new List<AttributeValue>
                    {
                        new AttributeValue { S = title2 },
                        new AttributeValue { N = year2.ToString() },
                    },
                }
            };

            var response = await Client.BatchExecuteStatementAsync(new BatchExecuteStatementRequest
            {
                Statements = statements,
            });

            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }

namespace PartiQL_Basics_Scenario
{
    public class PartiQLMethods
    {
        private static readonly AmazonDynamoDBClient Client = new AmazonDynamoDBClient();


        /// <summary>
        /// Inserts movies imported from a JSON file into the movie table by
        /// using an Amazon DynamoDB PartiQL INSERT statement.
        /// </summary>
        /// <param name="tableName">The name of the table where the movie
        /// information will be inserted.</param>
        /// <param name="movieFileName">The name of the JSON file that contains
        /// movie information.</param>
        /// <returns>A Boolean value that indicates the success or failure of
        /// the insert operation.</returns>
        public static async Task<bool> InsertMovies(string tableName, string movieFileName)
        {
            // Get the list of movies from the JSON file.
            var movies = ImportMovies(movieFileName);

            var success = false;

            if (movies is not null)
            {
                // Insert the movies in a batch using PartiQL. Because the
                // batch can contain a maximum of 25 items, insert 25 movies
                // at a time.
                string insertBatch = $"INSERT INTO {tableName} VALUE {{'title': ?, 'year': ?}}";
                var statements = new List<BatchStatementRequest>();

                try
                {
                    for (var indexOffset = 0; indexOffset < 250; indexOffset += 25)
                    {
                        for (var i = indexOffset; i < indexOffset + 25; i++)
                        {
                            statements.Add(new BatchStatementRequest
                            {
                                Statement = insertBatch,
                                Parameters = new List<AttributeValue>
                                {
                                    new AttributeValue { S = movies[i].Title },
                                    new AttributeValue { N = movies[i].Year.ToString() },
                                },
                            });
                        }

                        var response = await Client.BatchExecuteStatementAsync(new BatchExecuteStatementRequest
                        {
                            Statements = statements,
                        });

                        // Wait between batches for movies to be successfully added.
                        System.Threading.Thread.Sleep(3000);

                        success = response.HttpStatusCode == System.Net.HttpStatusCode.OK;

                        // Clear the list of statements for the next batch.
                        statements.Clear();
                    }
                }
                catch (AmazonDynamoDBException ex)
                {
                    Console.WriteLine(ex.Message);
                }
            }

            return success;
        }

        /// <summary>
        /// Loads the contents of a JSON file into a list of movies to be
        /// added to the DynamoDB table.
        /// </summary>
        /// <param name="movieFileName">The full path to the JSON file.</param>
        /// <returns>A generic list of movie objects.</returns>
        public static List<Movie> ImportMovies(string movieFileName)
        {
            if (!File.Exists(movieFileName))
            {
                return null!;
            }

            using var sr = new StreamReader(movieFileName);
            string json = sr.ReadToEnd();
            var allMovies = JsonConvert.DeserializeObject<List<Movie>>(json);

            if (allMovies is not null)
            {
                // Return the first 250 entries.
                return allMovies.GetRange(0, 250);
            }
            else
            {
                return null!;
            }
        }



        /// <summary>
        /// Uses a PartiQL SELECT statement to retrieve a single movie from the
        /// movie database.
        /// </summary>
        /// <param name="tableName">The name of the movie table.</param>
        /// <param name="movieTitle">The title of the movie to retrieve.</param>
        /// <returns>A list of movie data. If no movie matches the supplied
        /// title, the list is empty.</returns>
        public static async Task<List<Dictionary<string, AttributeValue>>> GetSingleMovie(string tableName, string movieTitle)
        {
            string selectSingle = $"SELECT * FROM {tableName} WHERE title = ?";
            var parameters = new List<AttributeValue>
            {
                new AttributeValue { S = movieTitle },
            };

            var response = await Client.ExecuteStatementAsync(new ExecuteStatementRequest
            {
                Statement = selectSingle,
                Parameters = parameters,
            });

            return response.Items;
        }



        /// <summary>
        /// Retrieve multiple movies by year using a SELECT statement.
        /// </summary>
        /// <param name="tableName">The name of the movie table.</param>
        /// <param name="year">The year the movies were released.</param>
        /// <returns></returns>
        public static async Task<List<Dictionary<string, AttributeValue>>> GetMovies(string tableName, int year)
        {
            string selectSingle = $"SELECT * FROM {tableName} WHERE year = ?";
            var parameters = new List<AttributeValue>
            {
                new AttributeValue { N = year.ToString() },
            };

            var response = await Client.ExecuteStatementAsync(new ExecuteStatementRequest
            {
                Statement = selectSingle,
                Parameters = parameters,
            });

            return response.Items;
        }


        /// <summary>
        /// Inserts a single movie into the movies table.
        /// </summary>
        /// <param name="tableName">The name of the table.</param>
        /// <param name="movieTitle">The title of the movie to insert.</param>
        /// <param name="year">The year that the movie was released.</param>
        /// <returns>A Boolean value that indicates the success or failure of
        /// the INSERT operation.</returns>
        public static async Task<bool> InsertSingleMovie(string tableName, string movieTitle, int year)
        {
            string insertBatch = $"INSERT INTO {tableName} VALUE {{'title': ?, 'year': ?}}";

            var response = await Client.ExecuteStatementAsync(new ExecuteStatementRequest
            {
                Statement = insertBatch,
                Parameters = new List<AttributeValue>
                {
                    new AttributeValue { S = movieTitle },
                    new AttributeValue { N = year.ToString() },
                },
            });

            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }



        /// <summary>
        /// Updates a single movie in the table, adding information for the
        /// producer.
        /// </summary>
        /// <param name="tableName">the name of the table.</param>
        /// <param name="producer">The name of the producer.</param>
        /// <param name="movieTitle">The movie title.</param>
        /// <param name="year">The year the movie was released.</param>
        /// <returns>A Boolean value that indicates the success of the
        /// UPDATE operation.</returns>
        public static async Task<bool> UpdateSingleMovie(string tableName, string producer, string movieTitle, int year)
        {
            string insertSingle = $"UPDATE {tableName} SET Producer=? WHERE title = ? AND year = ?";

            var response = await Client.ExecuteStatementAsync(new ExecuteStatementRequest
            {
                Statement = insertSingle,
                Parameters = new List<AttributeValue>
                {
                    new AttributeValue { S = producer },
                    new AttributeValue { S = movieTitle },
                    new AttributeValue { N = year.ToString() },
                },
            });

            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }



        /// <summary>
        /// Deletes a single movie from the table.
        /// </summary>
        /// <param name="tableName">The name of the table.</param>
        /// <param name="movieTitle">The title of the movie to delete.</param>
        /// <param name="year">The year that the movie was released.</param>
        /// <returns>A Boolean value that indicates the success of the
        /// DELETE operation.</returns>
        public static async Task<bool> DeleteSingleMovie(string tableName, string movieTitle, int year)
        {
            var deleteSingle = $"DELETE FROM {tableName} WHERE title = ? AND year = ?";

            var response = await Client.ExecuteStatementAsync(new ExecuteStatementRequest
            {
                Statement = deleteSingle,
                Parameters = new List<AttributeValue>
                {
                    new AttributeValue { S = movieTitle },
                    new AttributeValue { N = year.ToString() },
                },
            });

            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }


        /// <summary>
        /// Displays the list of movies returned from a database query.
        /// </summary>
        /// <param name="items">The list of movie information to display.</param>
        private static void DisplayMovies(List<Dictionary<string, AttributeValue>> items)
        {
            if (items.Count > 0)
            {
                Console.WriteLine($"Found {items.Count} movies.");
                items.ForEach(item => Console.WriteLine($"{item["year"].N}\t{item["title"].S}"));
            }
            else
            {
                Console.WriteLine($"Didn't find a movie that matched the supplied criteria.");
            }
        }


    }
}



        /// <summary>
        /// Uses a PartiQL SELECT statement to retrieve a single movie from the
        /// movie database.
        /// </summary>
        /// <param name="tableName">The name of the movie table.</param>
        /// <param name="movieTitle">The title of the movie to retrieve.</param>
        /// <returns>A list of movie data. If no movie matches the supplied
        /// title, the list is empty.</returns>
        public static async Task<List<Dictionary<string, AttributeValue>>> GetSingleMovie(string tableName, string movieTitle)
        {
            string selectSingle = $"SELECT * FROM {tableName} WHERE title = ?";
            var parameters = new List<AttributeValue>
            {
                new AttributeValue { S = movieTitle },
            };

            var response = await Client.ExecuteStatementAsync(new ExecuteStatementRequest
            {
                Statement = selectSingle,
                Parameters = parameters,
            });

            return response.Items;
        }



        /// <summary>
        /// Inserts a single movie into the movies table.
        /// </summary>
        /// <param name="tableName">The name of the table.</param>
        /// <param name="movieTitle">The title of the movie to insert.</param>
        /// <param name="year">The year that the movie was released.</param>
        /// <returns>A Boolean value that indicates the success or failure of
        /// the INSERT operation.</returns>
        public static async Task<bool> InsertSingleMovie(string tableName, string movieTitle, int year)
        {
            string insertBatch = $"INSERT INTO {tableName} VALUE {{'title': ?, 'year': ?}}";

            var response = await Client.ExecuteStatementAsync(new ExecuteStatementRequest
            {
                Statement = insertBatch,
                Parameters = new List<AttributeValue>
                {
                    new AttributeValue { S = movieTitle },
                    new AttributeValue { N = year.ToString() },
                },
            });

            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }



        /// <summary>
        /// Updates a single movie in the table, adding information for the
        /// producer.
        /// </summary>
        /// <param name="tableName">the name of the table.</param>
        /// <param name="producer">The name of the producer.</param>
        /// <param name="movieTitle">The movie title.</param>
        /// <param name="year">The year the movie was released.</param>
        /// <returns>A Boolean value that indicates the success of the
        /// UPDATE operation.</returns>
        public static async Task<bool> UpdateSingleMovie(string tableName, string producer, string movieTitle, int year)
        {
            string insertSingle = $"UPDATE {tableName} SET Producer=? WHERE title = ? AND year = ?";

            var response = await Client.ExecuteStatementAsync(new ExecuteStatementRequest
            {
                Statement = insertSingle,
                Parameters = new List<AttributeValue>
                {
                    new AttributeValue { S = producer },
                    new AttributeValue { S = movieTitle },
                    new AttributeValue { N = year.ToString() },
                },
            });

            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }



        /// <summary>
        /// Deletes a single movie from the table.
        /// </summary>
        /// <param name="tableName">The name of the table.</param>
        /// <param name="movieTitle">The title of the movie to delete.</param>
        /// <param name="year">The year that the movie was released.</param>
        /// <returns>A Boolean value that indicates the success of the
        /// DELETE operation.</returns>
        public static async Task<bool> DeleteSingleMovie(string tableName, string movieTitle, int year)
        {
            var deleteSingle = $"DELETE FROM {tableName} WHERE title = ? AND year = ?";

            var response = await Client.ExecuteStatementAsync(new ExecuteStatementRequest
            {
                Statement = deleteSingle,
                Parameters = new List<AttributeValue>
                {
                    new AttributeValue { S = movieTitle },
                    new AttributeValue { N = year.ToString() },
                },
            });

            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }

使用文档模型执行 CRUD 操作。

    /// <summary>
    /// Performs CRUD operations on an Amazon DynamoDB table.
    /// </summary>
    public class MidlevelItemCRUD
    {
        public static async Task Main()
        {
            var tableName = "ProductCatalog";
            var sampleBookId = 555;

            var client = new AmazonDynamoDBClient();
            var productCatalog = LoadTable(client, tableName);

            await CreateBookItem(productCatalog, sampleBookId);
            RetrieveBook(productCatalog, sampleBookId);

            // Couple of sample updates.
            UpdateMultipleAttributes(productCatalog, sampleBookId);
            UpdateBookPriceConditionally(productCatalog, sampleBookId);

            // Delete.
            await DeleteBook(productCatalog, sampleBookId);
        }

        /// <summary>
        /// Loads the contents of a DynamoDB table.
        /// </summary>
        /// <param name="client">An initialized DynamoDB client object.</param>
        /// <param name="tableName">The name of the table to load.</param>
        /// <returns>A DynamoDB table object.</returns>
        public static Table LoadTable(IAmazonDynamoDB client, string tableName)
        {
            Table productCatalog = Table.LoadTable(client, tableName);
            return productCatalog;
        }

        /// <summary>
        /// Creates an example book item and adds it to the DynamoDB table
        /// ProductCatalog.
        /// </summary>
        /// <param name="productCatalog">A DynamoDB table object.</param>
        /// <param name="sampleBookId">An integer value representing the book's ID.</param>
        public static async Task CreateBookItem(Table productCatalog, int sampleBookId)
        {
            Console.WriteLine("\n*** Executing CreateBookItem() ***");
            var book = new Document
            {
                ["Id"] = sampleBookId,
                ["Title"] = "Book " + sampleBookId,
                ["Price"] = 19.99,
                ["ISBN"] = "111-1111111111",
                ["Authors"] = new List<string> { "Author 1", "Author 2", "Author 3" },
                ["PageCount"] = 500,
                ["Dimensions"] = "8.5x11x.5",
                ["InPublication"] = new DynamoDBBool(true),
                ["InStock"] = new DynamoDBBool(false),
                ["QuantityOnHand"] = 0,
            };

            // Adds the book to the ProductCatalog table.
            await productCatalog.PutItemAsync(book);
        }

        /// <summary>
        /// Retrieves an item, a book, from the DynamoDB ProductCatalog table.
        /// </summary>
        /// <param name="productCatalog">A DynamoDB table object.</param>
        /// <param name="sampleBookId">An integer value representing the book's ID.</param>
        public static async void RetrieveBook(
          Table productCatalog,
          int sampleBookId)
        {
            Console.WriteLine("\n*** Executing RetrieveBook() ***");

            // Optional configuration.
            var config = new GetItemOperationConfig
            {
                AttributesToGet = new List<string> { "Id", "ISBN", "Title", "Authors", "Price" },
                ConsistentRead = true,
            };

            Document document = await productCatalog.GetItemAsync(sampleBookId, config);
            Console.WriteLine("RetrieveBook: Printing book retrieved...");
            PrintDocument(document);
        }

        /// <summary>
        /// Updates multiple attributes for a book and writes the changes to the
        /// DynamoDB table ProductCatalog.
        /// </summary>
        /// <param name="productCatalog">A DynamoDB table object.</param>
        /// <param name="sampleBookId">An integer value representing the book's ID.</param>
        public static async void UpdateMultipleAttributes(
          Table productCatalog,
          int sampleBookId)
        {
            Console.WriteLine("\nUpdating multiple attributes....");
            int partitionKey = sampleBookId;

            var book = new Document
            {
                ["Id"] = partitionKey,

                // List of attribute updates.
                // The following replaces the existing authors list.
                ["Authors"] = new List<string> { "Author x", "Author y" },
                ["newAttribute"] = "New Value",
                ["ISBN"] = null, // Remove it.
            };

            // Optional parameters.
            var config = new UpdateItemOperationConfig
            {
                // Gets updated item in response.
                ReturnValues = ReturnValues.AllNewAttributes,
            };

            Document updatedBook = await productCatalog.UpdateItemAsync(book, config);
            Console.WriteLine("UpdateMultipleAttributes: Printing item after updates ...");
            PrintDocument(updatedBook);
        }

        /// <summary>
        /// Updates a book item if it meets the specified criteria.
        /// </summary>
        /// <param name="productCatalog">A DynamoDB table object.</param>
        /// <param name="sampleBookId">An integer value representing the book's ID.</param>
        public static async void UpdateBookPriceConditionally(
          Table productCatalog,
          int sampleBookId)
        {
            Console.WriteLine("\n*** Executing UpdateBookPriceConditionally() ***");

            int partitionKey = sampleBookId;

            var book = new Document
            {
                ["Id"] = partitionKey,
                ["Price"] = 29.99,
            };

            // For conditional price update, creating a condition expression.
            var expr = new Expression
            {
                ExpressionStatement = "Price = :val",
            };
            expr.ExpressionAttributeValues[":val"] = 19.00;

            // Optional parameters.
            var config = new UpdateItemOperationConfig
            {
                ConditionalExpression = expr,
                ReturnValues = ReturnValues.AllNewAttributes,
            };

            Document updatedBook = await productCatalog.UpdateItemAsync(book, config);
            Console.WriteLine("UpdateBookPriceConditionally: Printing item whose price was conditionally updated");
            PrintDocument(updatedBook);
        }

        /// <summary>
        /// Deletes the book with the supplied Id value from the DynamoDB table
        /// ProductCatalog.
        /// </summary>
        /// <param name="productCatalog">A DynamoDB table object.</param>
        /// <param name="sampleBookId">An integer value representing the book's ID.</param>
        public static async Task DeleteBook(
          Table productCatalog,
          int sampleBookId)
        {
            Console.WriteLine("\n*** Executing DeleteBook() ***");

            // Optional configuration.
            var config = new DeleteItemOperationConfig
            {
                // Returns the deleted item.
                ReturnValues = ReturnValues.AllOldAttributes,
            };
            Document document = await productCatalog.DeleteItemAsync(sampleBookId, config);
            Console.WriteLine("DeleteBook: Printing deleted just deleted...");

            PrintDocument(document);
        }

        /// <summary>
        /// Prints the information for the supplied DynamoDB document.
        /// </summary>
        /// <param name="updatedDocument">A DynamoDB document object.</param>
        public static void PrintDocument(Document updatedDocument)
        {
            if (updatedDocument is null)
            {
                return;
            }

            foreach (var attribute in updatedDocument.GetAttributeNames())
            {
                string stringValue = null;
                var value = updatedDocument[attribute];

                if (value is null)
                {
                    continue;
                }

                if (value is Primitive)
                {
                    stringValue = value.AsPrimitive().Value.ToString();
                }
                else if (value is PrimitiveList)
                {
                    stringValue = string.Join(",", (from primitive
                      in value.AsPrimitiveList().Entries
                                                    select primitive.Value).ToArray());
                }

                Console.WriteLine($"{attribute} - {stringValue}", attribute, stringValue);
            }
        }
    }

使用文档模型执行批量写入操作。

    /// <summary>
    /// Shows how to use mid-level Amazon DynamoDB API calls to perform batch
    /// operations.
    /// </summary>
    public class MidLevelBatchWriteItem
    {
        public static async Task Main()
        {
            IAmazonDynamoDB client = new AmazonDynamoDBClient();

            await SingleTableBatchWrite(client);
            await MultiTableBatchWrite(client);
        }

        /// <summary>
        /// Perform a batch operation on a single DynamoDB table.
        /// </summary>
        /// <param name="client">An initialized DynamoDB object.</param>
        public static async Task SingleTableBatchWrite(IAmazonDynamoDB client)
        {
            Table productCatalog = Table.LoadTable(client, "ProductCatalog");
            var batchWrite = productCatalog.CreateBatchWrite();

            var book1 = new Document
            {
                ["Id"] = 902,
                ["Title"] = "My book1 in batch write using .NET helper classes",
                ["ISBN"] = "902-11-11-1111",
                ["Price"] = 10,
                ["ProductCategory"] = "Book",
                ["Authors"] = new List<string> { "Author 1", "Author 2", "Author 3" },
                ["Dimensions"] = "8.5x11x.5",
                ["InStock"] = new DynamoDBBool(true),
                ["QuantityOnHand"] = new DynamoDBNull(), // Quantity is unknown at this time.
            };

            batchWrite.AddDocumentToPut(book1);

            // Specify delete item using overload that takes PK.
            batchWrite.AddKeyToDelete(12345);
            Console.WriteLine("Performing batch write in SingleTableBatchWrite()");
            await batchWrite.ExecuteAsync();
        }

        /// <summary>
        /// Perform a batch operation involving multiple DynamoDB tables.
        /// </summary>
        /// <param name="client">An initialized DynamoDB client object.</param>
        public static async Task MultiTableBatchWrite(IAmazonDynamoDB client)
        {
            // Specify item to add in the Forum table.
            Table forum = Table.LoadTable(client, "Forum");
            var forumBatchWrite = forum.CreateBatchWrite();

            var forum1 = new Document
            {
                ["Name"] = "Test BatchWrite Forum",
                ["Threads"] = 0,
            };
            forumBatchWrite.AddDocumentToPut(forum1);

            // Specify item to add in the Thread table.
            Table thread = Table.LoadTable(client, "Thread");
            var threadBatchWrite = thread.CreateBatchWrite();

            var thread1 = new Document
            {
                ["ForumName"] = "S3 forum",
                ["Subject"] = "My sample question",
                ["Message"] = "Message text",
                ["KeywordTags"] = new List<string> { "S3", "Bucket" },
            };
            threadBatchWrite.AddDocumentToPut(thread1);

            // Specify item to delete from the Thread table.
            threadBatchWrite.AddKeyToDelete("someForumName", "someSubject");

            // Create multi-table batch.
            var superBatch = new MultiTableDocumentBatchWrite();
            superBatch.AddBatch(forumBatchWrite);
            superBatch.AddBatch(threadBatchWrite);
            Console.WriteLine("Performing batch write in MultiTableBatchWrite()");

            // Execute the batch.
            await superBatch.ExecuteAsync();
        }
    }

使用文档模型扫描表。

    /// <summary>
    /// Shows how to use mid-level Amazon DynamoDB API calls to scan a DynamoDB
    /// table for values.
    /// </summary>
    public class MidLevelScanOnly
    {
        public static async Task Main()
        {
            IAmazonDynamoDB client = new AmazonDynamoDBClient();

            Table productCatalogTable = Table.LoadTable(client, "ProductCatalog");

            await FindProductsWithNegativePrice(productCatalogTable);
            await FindProductsWithNegativePriceWithConfig(productCatalogTable);
        }

        /// <summary>
        /// Retrieves any products that have a negative price in a DynamoDB table.
        /// </summary>
        /// <param name="productCatalogTable">A DynamoDB table object.</param>
        public static async Task FindProductsWithNegativePrice(
          Table productCatalogTable)
        {
            // Assume there is a price error. So we scan to find items priced < 0.
            var scanFilter = new ScanFilter();
            scanFilter.AddCondition("Price", ScanOperator.LessThan, 0);

            Search search = productCatalogTable.Scan(scanFilter);

            do
            {
                var documentList = await search.GetNextSetAsync();
                Console.WriteLine("\nFindProductsWithNegativePrice: printing ............");

                foreach (var document in documentList)
                {
                    PrintDocument(document);
                }
            }
            while (!search.IsDone);
        }

        /// <summary>
        /// Finds any items in the ProductCatalog table using a DynamoDB
        /// configuration object.
        /// </summary>
        /// <param name="productCatalogTable">A DynamoDB table object.</param>
        public static async Task FindProductsWithNegativePriceWithConfig(
          Table productCatalogTable)
        {
            // Assume there is a price error. So we scan to find items priced < 0.
            var scanFilter = new ScanFilter();
            scanFilter.AddCondition("Price", ScanOperator.LessThan, 0);

            var config = new ScanOperationConfig()
            {
                Filter = scanFilter,
                Select = SelectValues.SpecificAttributes,
                AttributesToGet = new List<string> { "Title", "Id" },
            };

            Search search = productCatalogTable.Scan(config);

            do
            {
                var documentList = await search.GetNextSetAsync();
                Console.WriteLine("\nFindProductsWithNegativePriceWithConfig: printing ............");

                foreach (var document in documentList)
                {
                    PrintDocument(document);
                }
            }
            while (!search.IsDone);
        }

        /// <summary>
        /// Displays the details of the passed DynamoDB document object on the
        /// console.
        /// </summary>
        /// <param name="document">A DynamoDB document object.</param>
        public static void PrintDocument(Document document)
        {
            Console.WriteLine();
            foreach (var attribute in document.GetAttributeNames())
            {
                string stringValue = null;
                var value = document[attribute];
                if (value is Primitive)
                {
                    stringValue = value.AsPrimitive().Value.ToString();
                }
                else if (value is PrimitiveList)
                {
                    stringValue = string.Join(",", (from primitive
                      in value.AsPrimitiveList().Entries
                                                    select primitive.Value).ToArray());
                }

                Console.WriteLine($"{attribute} - {stringValue}");
            }
        }
    }

使用文档模型查询和扫描表。

    /// <summary>
    /// Shows how to perform mid-level query procedures on an Amazon DynamoDB
    /// table.
    /// </summary>
    public class MidLevelQueryAndScan
    {
        public static async Task Main()
        {
            IAmazonDynamoDB client = new AmazonDynamoDBClient();

            // Query examples.
            Table replyTable = Table.LoadTable(client, "Reply");
            string forumName = "Amazon DynamoDB";
            string threadSubject = "DynamoDB Thread 2";

            await FindRepliesInLast15Days(replyTable);
            await FindRepliesInLast15DaysWithConfig(replyTable, forumName, threadSubject);
            await FindRepliesPostedWithinTimePeriod(replyTable, forumName, threadSubject);

            // Get Example.
            Table productCatalogTable = Table.LoadTable(client, "ProductCatalog");
            int productId = 101;

            await GetProduct(productCatalogTable, productId);
        }

        /// <summary>
        /// Retrieves information about a product from the DynamoDB table
        /// ProductCatalog based on the product ID and displays the information
        /// on the console.
        /// </summary>
        /// <param name="tableName">The name of the table from which to retrieve
        /// product information.</param>
        /// <param name="productId">The ID of the product to retrieve.</param>
        public static async Task GetProduct(Table tableName, int productId)
        {
            Console.WriteLine("*** Executing GetProduct() ***");
            Document productDocument = await tableName.GetItemAsync(productId);
            if (productDocument != null)
            {
                PrintDocument(productDocument);
            }
            else
            {
                Console.WriteLine("Error: product " + productId + " does not exist");
            }
        }

        /// <summary>
        /// Retrieves replies from the passed DynamoDB table object.
        /// </summary>
        /// <param name="table">The table we want to query.</param>
        public static async Task FindRepliesInLast15Days(
          Table table)
        {
            DateTime twoWeeksAgoDate = DateTime.UtcNow - TimeSpan.FromDays(15);
            var filter = new QueryFilter("Id", QueryOperator.Equal, "Id");
            filter.AddCondition("ReplyDateTime", QueryOperator.GreaterThan, twoWeeksAgoDate);

            // Use Query overloads that take the minimum required query parameters.
            Search search = table.Query(filter);

            do
            {
                var documentSet = await search.GetNextSetAsync();
                Console.WriteLine("\nFindRepliesInLast15Days: printing ............");

                foreach (var document in documentSet)
                {
                    PrintDocument(document);
                }
            }
            while (!search.IsDone);
        }

        /// <summary>
        /// Retrieve replies made during a specific time period.
        /// </summary>
        /// <param name="table">The table we want to query.</param>
        /// <param name="forumName">The name of the forum that we're interested in.</param>
        /// <param name="threadSubject">The subject of the thread, which we are
        /// searching for replies.</param>
        public static async Task FindRepliesPostedWithinTimePeriod(
          Table table,
          string forumName,
          string threadSubject)
        {
            DateTime startDate = DateTime.UtcNow.Subtract(new TimeSpan(21, 0, 0, 0));
            DateTime endDate = DateTime.UtcNow.Subtract(new TimeSpan(1, 0, 0, 0));

            var filter = new QueryFilter("Id", QueryOperator.Equal, forumName + "#" + threadSubject);
            filter.AddCondition("ReplyDateTime", QueryOperator.Between, startDate, endDate);

            var config = new QueryOperationConfig()
            {
                Limit = 2, // 2 items/page.
                Select = SelectValues.SpecificAttributes,
                AttributesToGet = new List<string>
        {
          "Message",
          "ReplyDateTime",
          "PostedBy",
        },
                ConsistentRead = true,
                Filter = filter,
            };

            Search search = table.Query(config);

            do
            {
                var documentList = await search.GetNextSetAsync();
                Console.WriteLine("\nFindRepliesPostedWithinTimePeriod: printing replies posted within dates: {0} and {1} ............", startDate, endDate);

                foreach (var document in documentList)
                {
                    PrintDocument(document);
                }
            }
            while (!search.IsDone);
        }

        /// <summary>
        /// Perform a query for replies made in the last 15 days using a DynamoDB
        /// QueryOperationConfig object.
        /// </summary>
        /// <param name="table">The table we want to query.</param>
        /// <param name="forumName">The name of the forum that we're interested in.</param>
        /// <param name="threadName">The bane of the thread that we are searching
        /// for replies.</param>
        public static async Task FindRepliesInLast15DaysWithConfig(
          Table table,
          string forumName,
          string threadName)
        {
            DateTime twoWeeksAgoDate = DateTime.UtcNow - TimeSpan.FromDays(15);
            var filter = new QueryFilter("Id", QueryOperator.Equal, forumName + "#" + threadName);
            filter.AddCondition("ReplyDateTime", QueryOperator.GreaterThan, twoWeeksAgoDate);

            var config = new QueryOperationConfig()
            {
                Filter = filter,

                // Optional parameters.
                Select = SelectValues.SpecificAttributes,
                AttributesToGet = new List<string>
                {
                  "Message",
                  "ReplyDateTime",
                  "PostedBy",
                },
                ConsistentRead = true,
            };

            Search search = table.Query(config);

            do
            {
                var documentSet = await search.GetNextSetAsync();
                Console.WriteLine("\nFindRepliesInLast15DaysWithConfig: printing ............");

                foreach (var document in documentSet)
                {
                    PrintDocument(document);
                }
            }
            while (!search.IsDone);
        }

        /// <summary>
        /// Displays the contents of the passed DynamoDB document on the console.
        /// </summary>
        /// <param name="document">A DynamoDB document to display.</param>
        public static void PrintDocument(Document document)
        {
            Console.WriteLine();
            foreach (var attribute in document.GetAttributeNames())
            {
                string stringValue = null;
                var value = document[attribute];

                if (value is Primitive)
                {
                    stringValue = value.AsPrimitive().Value.ToString();
                }
                else if (value is PrimitiveList)
                {
                    stringValue = string.Join(",", (from primitive
                      in value.AsPrimitiveList().Entries
                                                    select primitive.Value).ToArray());
                }

                Console.WriteLine($"{attribute} - {stringValue}");
            }
        }
    }

使用高级对象持久化模型执行 CRUD 操作。

    /// <summary>
    /// Shows how to perform high-level CRUD operations on an Amazon DynamoDB
    /// table.
    /// </summary>
    public class HighLevelItemCrud
    {
        public static async Task Main()
        {
            var client = new AmazonDynamoDBClient();
            DynamoDBContext context = new DynamoDBContext(client);
            await PerformCRUDOperations(context);
        }

        public static async Task PerformCRUDOperations(IDynamoDBContext context)
        {
            int bookId = 1001; // Some unique value.
            Book myBook = new Book
            {
                Id = bookId,
                Title = "object persistence-AWS SDK for.NET SDK-Book 1001",
                Isbn = "111-1111111001",
                BookAuthors = new List<string> { "Author 1", "Author 2" },
            };

            // Save the book to the ProductCatalog table.
            await context.SaveAsync(myBook);

            // Retrieve the book from the ProductCatalog table.
            Book bookRetrieved = await context.LoadAsync<Book>(bookId);

            // Update some properties.
            bookRetrieved.Isbn = "222-2222221001";

            // Update existing authors list with the following values.
            bookRetrieved.BookAuthors = new List<string> { " Author 1", "Author x" };
            await context.SaveAsync(bookRetrieved);

            // Retrieve the updated book. This time, add the optional
            // ConsistentRead parameter using DynamoDBContextConfig object.
            await context.LoadAsync<Book>(bookId, new DynamoDBContextConfig
            {
                ConsistentRead = true,
            });

            // Delete the book.
            await context.DeleteAsync<Book>(bookId);

            // Try to retrieve deleted book. It should return null.
            Book deletedBook = await context.LoadAsync<Book>(bookId, new DynamoDBContextConfig
            {
                ConsistentRead = true,
            });

            if (deletedBook == null)
            {
                Console.WriteLine("Book is deleted");
            }
        }
    }

使用高级对象持久化模型执行批量写入操作。

    /// <summary>
    /// Performs high-level batch write operations to an Amazon DynamoDB table.
    /// This example was written using the AWS SDK for .NET version 3.7 and .NET
    /// Core 5.0.
    /// </summary>
    public class HighLevelBatchWriteItem
    {
        public static async Task SingleTableBatchWrite(IDynamoDBContext context)
        {
            Book book1 = new Book
            {
                Id = 902,
                InPublication = true,
                Isbn = "902-11-11-1111",
                PageCount = "100",
                Price = 10,
                ProductCategory = "Book",
                Title = "My book3 in batch write",
            };

            Book book2 = new Book
            {
                Id = 903,
                InPublication = true,
                Isbn = "903-11-11-1111",
                PageCount = "200",
                Price = 10,
                ProductCategory = "Book",
                Title = "My book4 in batch write",
            };

            var bookBatch = context.CreateBatchWrite<Book>();
            bookBatch.AddPutItems(new List<Book> { book1, book2 });

            Console.WriteLine("Adding two books to ProductCatalog table.");
            await bookBatch.ExecuteAsync();
        }

        public static async Task MultiTableBatchWrite(IDynamoDBContext context)
        {
            // New Forum item.
            Forum newForum = new Forum
            {
                Name = "Test BatchWrite Forum",
                Threads = 0,
            };
            var forumBatch = context.CreateBatchWrite<Forum>();
            forumBatch.AddPutItem(newForum);

            // New Thread item.
            Thread newThread = new Thread
            {
                ForumName = "S3 forum",
                Subject = "My sample question",
                KeywordTags = new List<string> { "S3", "Bucket" },
                Message = "Message text",
            };

            DynamoDBOperationConfig config = new DynamoDBOperationConfig();
            config.SkipVersionCheck = true;
            var threadBatch = context.CreateBatchWrite<Thread>(config);
            threadBatch.AddPutItem(newThread);
            threadBatch.AddDeleteKey("some partition key value", "some sort key value");

            var superBatch = new MultiTableBatchWrite(forumBatch, threadBatch);

            Console.WriteLine("Performing batch write in MultiTableBatchWrite().");
            await superBatch.ExecuteAsync();
        }

        public static async Task Main()
        {
            AmazonDynamoDBClient client = new AmazonDynamoDBClient();
            DynamoDBContext context = new DynamoDBContext(client);

            await SingleTableBatchWrite(context);
            await MultiTableBatchWrite(context);
        }
    }

使用高级对象持久化模型将任意数据映射为表。

    /// <summary>
    /// Shows how to map arbitrary data to an Amazon DynamoDB table.
    /// </summary>
    public class HighLevelMappingArbitraryData
    {
        /// <summary>
        /// Creates a book, adds it to the DynamoDB ProductCatalog table, retrieves
        /// the new book from the table, updates the dimensions and writes the
        /// changed item back to the table.
        /// </summary>
        /// <param name="context">The DynamoDB context object used to write and
        /// read data from the table.</param>
        public static async Task AddRetrieveUpdateBook(IDynamoDBContext context)
        {
            // Create a book.
            DimensionType myBookDimensions = new DimensionType()
            {
                Length = 8M,
                Height = 11M,
                Thickness = 0.5M,
            };

            Book myBook = new Book
            {
                Id = 501,
                Title = "AWS SDK for .NET Object Persistence Model Handling Arbitrary Data",
                Isbn = "999-9999999999",
                BookAuthors = new List<string> { "Author 1", "Author 2" },
                Dimensions = myBookDimensions,
            };

            // Add the book to the DynamoDB table ProductCatalog.
            await context.SaveAsync(myBook);

            // Retrieve the book.
            Book bookRetrieved = await context.LoadAsync<Book>(501);

            // Update the book dimensions property.
            bookRetrieved.Dimensions.Height += 1;
            bookRetrieved.Dimensions.Length += 1;
            bookRetrieved.Dimensions.Thickness += 0.2M;

            // Write the changed item to the table.
            await context.SaveAsync(bookRetrieved);
        }

        public static async Task Main()
        {
            var client = new AmazonDynamoDBClient();
            DynamoDBContext context = new DynamoDBContext(client);
            await AddRetrieveUpdateBook(context);
        }
    }

使用高级对象持久化模型查询和扫描表。

    /// <summary>
    /// Shows how to perform high-level query and scan operations to Amazon
    /// DynamoDB tables.
    /// </summary>
    public class HighLevelQueryAndScan
    {
        public static async Task Main()
        {
            var client = new AmazonDynamoDBClient();

            DynamoDBContext context = new DynamoDBContext(client);

            // Get an item.
            await GetBook(context, 101);

            // Sample forum and thread to test queries.
            string forumName = "Amazon DynamoDB";
            string threadSubject = "DynamoDB Thread 1";

            // Sample queries.
            await FindRepliesInLast15Days(context, forumName, threadSubject);
            await FindRepliesPostedWithinTimePeriod(context, forumName, threadSubject);

            // Scan table.
            await FindProductsPricedLessThanZero(context);
        }

        public static async Task GetBook(IDynamoDBContext context, int productId)
        {
            Book bookItem = await context.LoadAsync<Book>(productId);

            Console.WriteLine("\nGetBook: Printing result.....");
            Console.WriteLine($"Title: {bookItem.Title} \n ISBN:{bookItem.Isbn} \n No. of pages: {bookItem.PageCount}");
        }

        /// <summary>
        /// Queries a DynamoDB table to find replies posted within the last 15 days.
        /// </summary>
        /// <param name="context">The DynamoDB context used to perform the query.</param>
        /// <param name="forumName">The name of the forum that we're interested in.</param>
        /// <param name="threadSubject">The thread object containing the query parameters.</param>
        public static async Task FindRepliesInLast15Days(
          IDynamoDBContext context,
          string forumName,
          string threadSubject)
        {
            string replyId = $"{forumName} #{threadSubject}";
            DateTime twoWeeksAgoDate = DateTime.UtcNow - TimeSpan.FromDays(15);

            List<object> times = new List<object>();
            times.Add(twoWeeksAgoDate);

            List<ScanCondition> scs = new List<ScanCondition>();
            var sc = new ScanCondition("PostedBy", ScanOperator.GreaterThan, times.ToArray());
            scs.Add(sc);

            var cfg = new DynamoDBOperationConfig
            {
                QueryFilter = scs,
            };

            AsyncSearch<Reply> response = context.QueryAsync<Reply>(replyId, cfg);
            IEnumerable<Reply> latestReplies = await response.GetRemainingAsync();

            Console.WriteLine("\nReplies in last 15 days:");

            foreach (Reply r in latestReplies)
            {
                Console.WriteLine($"{r.Id}\t{r.PostedBy}\t{r.Message}\t{r.ReplyDateTime}");
            }
        }

        /// <summary>
        /// Queries for replies posted within a specific time period.
        /// </summary>
        /// <param name="context">The DynamoDB context used to perform the query.</param>
        /// <param name="forumName">The name of the forum that we're interested in.</param>
        /// <param name="threadSubject">Information about the subject that we're
        /// interested in.</param>
        public static async Task FindRepliesPostedWithinTimePeriod(
          IDynamoDBContext context,
          string forumName,
          string threadSubject)
        {
            string forumId = forumName + "#" + threadSubject;
            Console.WriteLine("\nReplies posted within time period:");

            DateTime startDate = DateTime.UtcNow - TimeSpan.FromDays(30);
            DateTime endDate = DateTime.UtcNow - TimeSpan.FromDays(1);

            List<object> times = new List<object>();
            times.Add(startDate);
            times.Add(endDate);

            List<ScanCondition> scs = new List<ScanCondition>();
            var sc = new ScanCondition("LastPostedBy", ScanOperator.Between, times.ToArray());
            scs.Add(sc);

            var cfg = new DynamoDBOperationConfig
            {
                QueryFilter = scs,
            };

            AsyncSearch<Reply> response = context.QueryAsync<Reply>(forumId, cfg);
            IEnumerable<Reply> repliesInAPeriod = await response.GetRemainingAsync();

            foreach (Reply r in repliesInAPeriod)
            {
                Console.WriteLine("{r.Id}\t{r.PostedBy}\t{r.Message}\t{r.ReplyDateTime}");
            }
        }

        /// <summary>
        /// Queries the DynamoDB ProductCatalog table for products costing less
        /// than zero.
        /// </summary>
        /// <param name="context">The DynamoDB context object used to perform the
        /// query.</param>
        public static async Task FindProductsPricedLessThanZero(IDynamoDBContext context)
        {
            int price = 0;

            List<ScanCondition> scs = new List<ScanCondition>();
            var sc1 = new ScanCondition("Price", ScanOperator.LessThan, price);
            var sc2 = new ScanCondition("ProductCategory", ScanOperator.Equal, "Book");
            scs.Add(sc1);
            scs.Add(sc2);

            AsyncSearch<Book> response = context.ScanAsync<Book>(scs);

            IEnumerable<Book> itemsWithWrongPrice = await response.GetRemainingAsync();

            Console.WriteLine("\nFindProductsPricedLessThanZero: Printing result.....");

            foreach (Book r in itemsWithWrongPrice)
            {
                Console.WriteLine($"{r.Id}\t{r.Title}\t{r.Price}\t{r.Isbn}");
            }
        }
    }