本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。
# 在 中使用資料表 DynamoDB
資料表是 DynamoDB 資料庫中所有項目的容器。您必須先建立資料表 DynamoDB，才能從中新增或移除資料。
對於每個資料表，您必須定義：
+ 您帳戶和區域唯一的資料表*名稱*。
+ 每個值的*主索引鍵*都必須獨一無二，資料表中任兩個項目不能有相同的主索引鍵值。
主索引鍵可以是*簡單的*，包含單一分割區 (HASH) 索引鍵；也可以是*複合的*，包含分割區和排序 (RANGE) 索引鍵。
每個索引鍵值都有一個相關聯的*資料類型*，由 [https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/dynamodb/model/ScalarAttributeType.html](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/dynamodb/model/ScalarAttributeType.html)類別列舉。索引鍵值可以是二進位 (B)、數值 (N)、或字串 (S)。如需詳細資訊，請參閱《 Amazon DynamoDB 開發人員指南》中的[命名規則和資料類型](https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/HowItWorks.NamingRulesDataTypes.html)。
+ *佈建輸送量*值用於定義為資料表預留的讀取/寫入容量單位數。
**注意**
[Amazon DynamoDB 定價](https://aws.amazon.com/dynamodb/pricing/)是以您在資料表上設定的佈建輸送量值為基礎，因此請只預留您認為資料表所需的容量。
資料表的佈建輸送量隨時可以修改，所以您可以在需求變更時調整容量。
## 建立資料表
使用 `DynamoDbClient’s``createTable`方法來建立新的 DynamoDB 資料表。您需要建構資料表屬性和資料表結構描述，這兩項都會用來識別資料表的主索引鍵。您也必須提供初始佈建的輸送量值和資料表名稱。
**注意**
如果具有您所選名稱的資料表已存在，`[DynamoDbException](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/dynamodb/model/DynamoDbException.html)`則會擲回 。
### 使用簡單主索引鍵建立資料表
此程式碼會建立一個具有一個屬性的資料表，該屬性是資料表的簡單主索引鍵。 範例使用 `[AttributeDefinition](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/dynamodb/model/AttributeDefinition.html)`和 `[KeySchemaElement](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/dynamodb/model/KeySchemaElement.html)` 物件做為 [https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/dynamodb/model/CreateTableRequest.html](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/dynamodb/model/CreateTableRequest.html)。
**匯入**
```
import software.amazon.awssdk.core.waiters.WaiterResponse;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.dynamodb.model.CreateTableRequest;
import software.amazon.awssdk.services.dynamodb.model.AttributeDefinition;
import software.amazon.awssdk.services.dynamodb.model.ScalarAttributeType;
import software.amazon.awssdk.services.dynamodb.model.ScalarAttributeType;
import software.amazon.awssdk.services.dynamodb.model.KeySchemaElement;
import software.amazon.awssdk.services.dynamodb.model.ProvisionedThroughput;
import software.amazon.awssdk.services.dynamodb.model.KeyType;
import software.amazon.awssdk.services.dynamodb.model.CreateTableResponse;
import software.amazon.awssdk.services.dynamodb.model.DescribeTableRequest;
import software.amazon.awssdk.services.dynamodb.model.DescribeTableResponse;
import software.amazon.awssdk.services.dynamodb.model.DynamoDbException;
import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
import software.amazon.awssdk.services.dynamodb.waiters.DynamoDbWaiter;
```
**Code**
```
public static String createTable(DynamoDbClient ddb, String tableName, String key) {
DynamoDbWaiter dbWaiter = ddb.waiter();
CreateTableRequest request = CreateTableRequest.builder()
.attributeDefinitions(AttributeDefinition.builder()
.attributeName(key)
.attributeType(ScalarAttributeType.S)
.build())
.keySchema(KeySchemaElement.builder()
.attributeName(key)
.keyType(KeyType.HASH)
.build())
.provisionedThroughput(ProvisionedThroughput.builder()
.readCapacityUnits(new Long(10))
.writeCapacityUnits(new Long(10))
.build())
.tableName(tableName)
.build();
String newTable ="";
try {
CreateTableResponse response = ddb.createTable(request);
DescribeTableRequest tableRequest = DescribeTableRequest.builder()
.tableName(tableName)
.build();
// Wait until the Amazon DynamoDB table is created
WaiterResponse waiterResponse = dbWaiter.waitUntilTableExists(tableRequest);
waiterResponse.matched().response().ifPresent(System.out::println);
newTable = response.tableDescription().tableName();
return newTable;
} catch (DynamoDbException e) {
System.err.println(e.getMessage());
System.exit(1);
}
return "";
}
```
請參閱 GitHub 上的[完整範例](https://github.com/awsdocs/aws-doc-sdk-examples/blob/0b1785e42949ebf959eaa0f0da4dc2a48f92ea25/javav2/example_code/dynamodb/src/main/java/com/example/dynamodb/CreateTable.java)。
### 使用複合主索引鍵建立資料表
下列範例會建立具有兩個屬性的資料表。這兩個屬性都用於複合主索引鍵。
**匯入**
```
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.dynamodb.model.DynamoDbException;
import software.amazon.awssdk.services.dynamodb.model.AttributeDefinition;
import software.amazon.awssdk.services.dynamodb.model.CreateTableRequest;
import software.amazon.awssdk.services.dynamodb.model.CreateTableResponse;
import software.amazon.awssdk.services.dynamodb.model.KeySchemaElement;
import software.amazon.awssdk.services.dynamodb.model.KeyType;
import software.amazon.awssdk.services.dynamodb.model.ProvisionedThroughput;
import software.amazon.awssdk.services.dynamodb.model.ScalarAttributeType;
import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
```
**Code**
```
public static String createTableComKey(DynamoDbClient ddb, String tableName) {
CreateTableRequest request = CreateTableRequest.builder()
.attributeDefinitions(
AttributeDefinition.builder()
.attributeName("Language")
.attributeType(ScalarAttributeType.S)
.build(),
AttributeDefinition.builder()
.attributeName("Greeting")
.attributeType(ScalarAttributeType.S)
.build())
.keySchema(
KeySchemaElement.builder()
.attributeName("Language")
.keyType(KeyType.HASH)
.build(),
KeySchemaElement.builder()
.attributeName("Greeting")
.keyType(KeyType.RANGE)
.build())
.provisionedThroughput(
ProvisionedThroughput.builder()
.readCapacityUnits(new Long(10))
.writeCapacityUnits(new Long(10)).build())
.tableName(tableName)
.build();
String tableId = "";
try {
CreateTableResponse result = ddb.createTable(request);
tableId = result.tableDescription().tableId();
return tableId;
} catch (DynamoDbException e) {
System.err.println(e.getMessage());
System.exit(1);
}
return "";
}
```
請參閱 GitHub 上的[完整範例](https://github.com/awsdocs/aws-doc-sdk-examples/blob/0b1785e42949ebf959eaa0f0da4dc2a48f92ea25/javav2/example_code/dynamodb/src/main/java/com/example/dynamodb/CreateTableCompositeKey.java)。
## 列出資料表
您可以透過呼叫 `DynamoDbClient’s``listTables`方法列出特定區域中的資料表。
**注意**
如果您的帳戶和區域不存在具名資料表，[https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/dynamodb/model/ResourceNotFoundException.html](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/dynamodb/model/ResourceNotFoundException.html)則會擲回 。
**匯入**
```
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.dynamodb.model.DynamoDbException;
import software.amazon.awssdk.services.dynamodb.model.ListTablesResponse;
import software.amazon.awssdk.services.dynamodb.model.ListTablesRequest;
import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
import java.util.List;
```
**Code**
```
public static void listAllTables(DynamoDbClient ddb){
boolean moreTables = true;
String lastName = null;
while(moreTables) {
try {
ListTablesResponse response = null;
if (lastName == null) {
ListTablesRequest request = ListTablesRequest.builder().build();
response = ddb.listTables(request);
} else {
ListTablesRequest request = ListTablesRequest.builder()
.exclusiveStartTableName(lastName).build();
response = ddb.listTables(request);
}
List tableNames = response.tableNames();
if (tableNames.size() > 0) {
for (String curName : tableNames) {
System.out.format("* %s\n", curName);
}
} else {
System.out.println("No tables found!");
System.exit(0);
}
lastName = response.lastEvaluatedTableName();
if (lastName == null) {
moreTables = false;
}
} catch (DynamoDbException e) {
System.err.println(e.getMessage());
System.exit(1);
}
}
System.out.println("\nDone!");
}
```
根據預設，每次呼叫最多傳回 100 個資料表 - 在傳回的[https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/dynamodb/model/ListTablesResponse.html](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/dynamodb/model/ListTablesResponse.html)物件`lastEvaluatedTableName`上使用 以取得上次評估的資料表。您可以使用這個值，在前次列表最後傳回值之後開始列表。
請參閱 GitHub 上的[完整範例](https://github.com/awsdocs/aws-doc-sdk-examples/blob/0b1785e42949ebf959eaa0f0da4dc2a48f92ea25/javav2/example_code/dynamodb/src/main/java/com/example/dynamodb/ListTables.java)。
## 描述資料表 (取得其相關資訊)
使用 `DynamoDbClient’s``describeTable`方法取得資料表的相關資訊。
**注意**
如果您的帳戶和區域不存在具名資料表，[https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/dynamodb/model/ResourceNotFoundException.html](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/dynamodb/model/ResourceNotFoundException.html)則會擲出 。
**匯入**
```
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.dynamodb.model.DynamoDbException;
import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
import software.amazon.awssdk.services.dynamodb.model.AttributeDefinition;
import software.amazon.awssdk.services.dynamodb.model.DescribeTableRequest;
import software.amazon.awssdk.services.dynamodb.model.ProvisionedThroughputDescription;
import software.amazon.awssdk.services.dynamodb.model.TableDescription;
import java.util.List;
```
**Code**
```
public static void describeDymamoDBTable(DynamoDbClient ddb,String tableName ) {
DescribeTableRequest request = DescribeTableRequest.builder()
.tableName(tableName)
.build();
try {
TableDescription tableInfo =
ddb.describeTable(request).table();
if (tableInfo != null) {
System.out.format("Table name : %s\n",
tableInfo.tableName());
System.out.format("Table ARN : %s\n",
tableInfo.tableArn());
System.out.format("Status : %s\n",
tableInfo.tableStatus());
System.out.format("Item count : %d\n",
tableInfo.itemCount().longValue());
System.out.format("Size (bytes): %d\n",
tableInfo.tableSizeBytes().longValue());
ProvisionedThroughputDescription throughputInfo =
tableInfo.provisionedThroughput();
System.out.println("Throughput");
System.out.format(" Read Capacity : %d\n",
throughputInfo.readCapacityUnits().longValue());
System.out.format(" Write Capacity: %d\n",
throughputInfo.writeCapacityUnits().longValue());
List attributes =
tableInfo.attributeDefinitions();
System.out.println("Attributes");
for (AttributeDefinition a : attributes) {
System.out.format(" %s (%s)\n",
a.attributeName(), a.attributeType());
}
}
} catch (DynamoDbException e) {
System.err.println(e.getMessage());
System.exit(1);
}
System.out.println("\nDone!");
}
```
請參閱 GitHub 上的[完整範例](https://github.com/awsdocs/aws-doc-sdk-examples/blob/0b1785e42949ebf959eaa0f0da4dc2a48f92ea25/javav2/example_code/dynamodb/src/main/java/com/example/dynamodb/DescribeTable.java)。
## 修改 (更新) 資料表
您可以隨時呼叫 `DynamoDbClient’s``updateTable`方法修改資料表的佈建輸送量值。
**注意**
如果您的 帳戶和區域不存在具名資料表，則會擲回 [ResourceNotFoundException](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/dynamodb/model/ResourceNotFoundException.html)。
**匯入**
```
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.dynamodb.model.ProvisionedThroughput;
import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
import software.amazon.awssdk.services.dynamodb.model.UpdateTableRequest;
import software.amazon.awssdk.services.dynamodb.model.DynamoDbException;
```
**Code**
```
public static void updateDynamoDBTable(DynamoDbClient ddb,
String tableName,
Long readCapacity,
Long writeCapacity) {
System.out.format(
"Updating %s with new provisioned throughput values\n",
tableName);
System.out.format("Read capacity : %d\n", readCapacity);
System.out.format("Write capacity : %d\n", writeCapacity);
ProvisionedThroughput tableThroughput = ProvisionedThroughput.builder()
.readCapacityUnits(readCapacity)
.writeCapacityUnits(writeCapacity)
.build();
UpdateTableRequest request = UpdateTableRequest.builder()
.provisionedThroughput(tableThroughput)
.tableName(tableName)
.build();
try {
ddb.updateTable(request);
} catch (DynamoDbException e) {
System.err.println(e.getMessage());
System.exit(1);
}
System.out.println("Done!");
}
```
請參閱 GitHub 上的[完整範例](https://github.com/awsdocs/aws-doc-sdk-examples/blob/0b1785e42949ebf959eaa0f0da4dc2a48f92ea25/javav2/example_code/dynamodb/src/main/java/com/example/dynamodb/UpdateTable.java)。
## 刪除資料表
若要刪除資料表，請呼叫 `DynamoDbClient’s` `deleteTable` 方法並提供資料表的名稱。
**注意**
如果您的帳戶和區域不存在具名資料表，則會擲回 [ResourceNotFoundException](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/dynamodb/model/ResourceNotFoundException.html)。
**匯入**
```
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.dynamodb.model.DynamoDbException;
import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
import software.amazon.awssdk.services.dynamodb.model.DeleteTableRequest;
```
**Code**
```
public static void deleteDynamoDBTable(DynamoDbClient ddb, String tableName) {
DeleteTableRequest request = DeleteTableRequest.builder()
.tableName(tableName)
.build();
try {
ddb.deleteTable(request);
} catch (DynamoDbException e) {
System.err.println(e.getMessage());
System.exit(1);
}
System.out.println(tableName +" was successfully deleted!");
}
```
請參閱 GitHub 上的[完整範例](https://github.com/awsdocs/aws-doc-sdk-examples/blob/0b1785e42949ebf959eaa0f0da4dc2a48f92ea25/javav2/example_code/dynamodb/src/main/java/com/example/dynamodb/DeleteTable.java)。
## 其他資訊
+ 《 Amazon DynamoDB 開發人員指南》中的[使用資料表的指導方針](https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/GuidelinesForTables.html)
+ 《 Amazon DynamoDB 開發人員指南》中的[在 中使用資料表 DynamoDB](https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/WorkingWithTables.html)