UpdateItemCommand

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Edits an existing item's attributes, or adds a new item to the table if it does not already exist. You can put, delete, or add attribute values. You can also perform a conditional update on an existing item (insert a new attribute name-value pair if it doesn't exist, or replace an existing name-value pair if it has certain expected attribute values).

You can also return the item's attribute values in the same UpdateItem operation using the ReturnValues parameter.

Example Syntax

Use a bare-bones client and the command you need to make an API call.

import { DynamoDBClient, UpdateItemCommand } from "@aws-sdk/client-dynamodb"; // ES Modules import
// const { DynamoDBClient, UpdateItemCommand } = require("@aws-sdk/client-dynamodb"); // CommonJS import
const client = new DynamoDBClient(config);
const input = { // UpdateItemInput
  TableName: "STRING_VALUE", // required
  Key: { // Key // required
    "<keys>": { // AttributeValue Union: only one key present
      S: "STRING_VALUE",
      N: "STRING_VALUE",
      B: new Uint8Array(), // e.g. Buffer.from("") or new TextEncoder().encode("")
      SS: [ // StringSetAttributeValue
        "STRING_VALUE",
      ],
      NS: [ // NumberSetAttributeValue
        "STRING_VALUE",
      ],
      BS: [ // BinarySetAttributeValue
        new Uint8Array(), // e.g. Buffer.from("") or new TextEncoder().encode("")
      ],
      M: { // MapAttributeValue
        "<keys>": {//  Union: only one key present
          S: "STRING_VALUE",
          N: "STRING_VALUE",
          B: new Uint8Array(), // e.g. Buffer.from("") or new TextEncoder().encode("")
          SS: [
            "STRING_VALUE",
          ],
          NS: [
            "STRING_VALUE",
          ],
          BS: [
            new Uint8Array(), // e.g. Buffer.from("") or new TextEncoder().encode("")
          ],
          M: {
            "<keys>": "<AttributeValue>",
          },
          L: [ // ListAttributeValue
            "<AttributeValue>",
          ],
          NULL: true || false,
          BOOL: true || false,
        },
      },
      L: [
        "<AttributeValue>",
      ],
      NULL: true || false,
      BOOL: true || false,
    },
  },
  AttributeUpdates: { // AttributeUpdates
    "<keys>": { // AttributeValueUpdate
      Value: "<AttributeValue>",
      Action: "ADD" || "PUT" || "DELETE",
    },
  },
  Expected: { // ExpectedAttributeMap
    "<keys>": { // ExpectedAttributeValue
      Value: "<AttributeValue>",
      Exists: true || false,
      ComparisonOperator: "EQ" || "NE" || "IN" || "LE" || "LT" || "GE" || "GT" || "BETWEEN" || "NOT_NULL" || "NULL" || "CONTAINS" || "NOT_CONTAINS" || "BEGINS_WITH",
      AttributeValueList: [ // AttributeValueList
        "<AttributeValue>",
      ],
    },
  },
  ConditionalOperator: "AND" || "OR",
  ReturnValues: "NONE" || "ALL_OLD" || "UPDATED_OLD" || "ALL_NEW" || "UPDATED_NEW",
  ReturnConsumedCapacity: "INDEXES" || "TOTAL" || "NONE",
  ReturnItemCollectionMetrics: "SIZE" || "NONE",
  UpdateExpression: "STRING_VALUE",
  ConditionExpression: "STRING_VALUE",
  ExpressionAttributeNames: { // ExpressionAttributeNameMap
    "<keys>": "STRING_VALUE",
  },
  ExpressionAttributeValues: { // ExpressionAttributeValueMap
    "<keys>": "<AttributeValue>",
  },
  ReturnValuesOnConditionCheckFailure: "ALL_OLD" || "NONE",
};
const command = new UpdateItemCommand(input);
const response = await client.send(command);
// { // UpdateItemOutput
//   Attributes: { // AttributeMap
//     "<keys>": { // AttributeValue Union: only one key present
//       S: "STRING_VALUE",
//       N: "STRING_VALUE",
//       B: new Uint8Array(),
//       SS: [ // StringSetAttributeValue
//         "STRING_VALUE",
//       ],
//       NS: [ // NumberSetAttributeValue
//         "STRING_VALUE",
//       ],
//       BS: [ // BinarySetAttributeValue
//         new Uint8Array(),
//       ],
//       M: { // MapAttributeValue
//         "<keys>": {//  Union: only one key present
//           S: "STRING_VALUE",
//           N: "STRING_VALUE",
//           B: new Uint8Array(),
//           SS: [
//             "STRING_VALUE",
//           ],
//           NS: [
//             "STRING_VALUE",
//           ],
//           BS: [
//             new Uint8Array(),
//           ],
//           M: {
//             "<keys>": "<AttributeValue>",
//           },
//           L: [ // ListAttributeValue
//             "<AttributeValue>",
//           ],
//           NULL: true || false,
//           BOOL: true || false,
//         },
//       },
//       L: [
//         "<AttributeValue>",
//       ],
//       NULL: true || false,
//       BOOL: true || false,
//     },
//   },
//   ConsumedCapacity: { // ConsumedCapacity
//     TableName: "STRING_VALUE",
//     CapacityUnits: Number("double"),
//     ReadCapacityUnits: Number("double"),
//     WriteCapacityUnits: Number("double"),
//     Table: { // Capacity
//       ReadCapacityUnits: Number("double"),
//       WriteCapacityUnits: Number("double"),
//       CapacityUnits: Number("double"),
//     },
//     LocalSecondaryIndexes: { // SecondaryIndexesCapacityMap
//       "<keys>": {
//         ReadCapacityUnits: Number("double"),
//         WriteCapacityUnits: Number("double"),
//         CapacityUnits: Number("double"),
//       },
//     },
//     GlobalSecondaryIndexes: {
//       "<keys>": {
//         ReadCapacityUnits: Number("double"),
//         WriteCapacityUnits: Number("double"),
//         CapacityUnits: Number("double"),
//       },
//     },
//   },
//   ItemCollectionMetrics: { // ItemCollectionMetrics
//     ItemCollectionKey: { // ItemCollectionKeyAttributeMap
//       "<keys>": "<AttributeValue>",
//     },
//     SizeEstimateRangeGB: [ // ItemCollectionSizeEstimateRange
//       Number("double"),
//     ],
//   },
// };

Example Usage

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UpdateItemCommand Input

See UpdateItemCommandInput for more details

Parameter
Type
Description
Key
Required
Record<string, AttributeValue> | undefined

The primary key of the item to be updated. Each element consists of an attribute name and a value for that attribute.

For the primary key, you must provide all of the attributes. For example, with a simple primary key, you only need to provide a value for the partition key. For a composite primary key, you must provide values for both the partition key and the sort key.

TableName
Required
string | undefined

The name of the table containing the item to update. You can also provide the Amazon Resource Name (ARN) of the table in this parameter.

AttributeUpdates
Record<string, AttributeValueUpdate> | undefined

This is a legacy parameter. Use UpdateExpression instead. For more information, see AttributeUpdates  in the Amazon DynamoDB Developer Guide.

ConditionExpression
string | undefined

A condition that must be satisfied in order for a conditional update to succeed.

An expression can contain any of the following:

  • Functions: attribute_exists | attribute_not_exists | attribute_type | contains | begins_with | size

    These function names are case-sensitive.

  • Comparison operators: = | | | | = | = | BETWEEN | IN

  • Logical operators: AND | OR | NOT

For more information about condition expressions, see Specifying Conditions  in the Amazon DynamoDB Developer Guide.

ConditionalOperator
ConditionalOperator | undefined

This is a legacy parameter. Use ConditionExpression instead. For more information, see ConditionalOperator  in the Amazon DynamoDB Developer Guide.

Expected
Record<string, ExpectedAttributeValue> | undefined

This is a legacy parameter. Use ConditionExpression instead. For more information, see Expected  in the Amazon DynamoDB Developer Guide.

ExpressionAttributeNames
Record<string, string> | undefined

One or more substitution tokens for attribute names in an expression. The following are some use cases for using ExpressionAttributeNames:

  • To access an attribute whose name conflicts with a DynamoDB reserved word.

  • To create a placeholder for repeating occurrences of an attribute name in an expression.

  • To prevent special characters in an attribute name from being misinterpreted in an expression.

Use the # character in an expression to dereference an attribute name. For example, consider the following attribute name:

  • Percentile

The name of this attribute conflicts with a reserved word, so it cannot be used directly in an expression. (For the complete list of reserved words, see Reserved Words  in the Amazon DynamoDB Developer Guide.) To work around this, you could specify the following for ExpressionAttributeNames:

  • {"#P":"Percentile"}

You could then use this substitution in an expression, as in this example:

  • #P = :val

Tokens that begin with the : character are expression attribute values, which are placeholders for the actual value at runtime.

For more information about expression attribute names, see Specifying Item Attributes  in the Amazon DynamoDB Developer Guide.

ExpressionAttributeValues
Record<string, AttributeValue> | undefined

One or more values that can be substituted in an expression.

Use the : (colon) character in an expression to dereference an attribute value. For example, suppose that you wanted to check whether the value of the ProductStatus attribute was one of the following:

Available | Backordered | Discontinued

You would first need to specify ExpressionAttributeValues as follows:

{ ":avail":{"S":"Available"}, ":back":{"S":"Backordered"}, ":disc":{"S":"Discontinued"} }

You could then use these values in an expression, such as this:

ProductStatus IN (:avail, :back, :disc)

For more information on expression attribute values, see Condition Expressions  in the Amazon DynamoDB Developer Guide.

ReturnConsumedCapacity
ReturnConsumedCapacity | undefined

Determines the level of detail about either provisioned or on-demand throughput consumption that is returned in the response:

  • INDEXES - The response includes the aggregate ConsumedCapacity for the operation, together with ConsumedCapacity for each table and secondary index that was accessed.

    Note that some operations, such as GetItem and BatchGetItem, do not access any indexes at all. In these cases, specifying INDEXES will only return ConsumedCapacity information for table(s).

  • TOTAL - The response includes only the aggregate ConsumedCapacity for the operation.

  • NONE - No ConsumedCapacity details are included in the response.

ReturnItemCollectionMetrics
ReturnItemCollectionMetrics | undefined

Determines whether item collection metrics are returned. If set to SIZE, the response includes statistics about item collections, if any, that were modified during the operation are returned in the response. If set to NONE (the default), no statistics are returned.

ReturnValues
ReturnValue | undefined

Use ReturnValues if you want to get the item attributes as they appear before or after they are successfully updated. For UpdateItem, the valid values are:

  • NONE - If ReturnValues is not specified, or if its value is NONE, then nothing is returned. (This setting is the default for ReturnValues.)

  • ALL_OLD - Returns all of the attributes of the item, as they appeared before the UpdateItem operation.

  • UPDATED_OLD - Returns only the updated attributes, as they appeared before the UpdateItem operation.

  • ALL_NEW - Returns all of the attributes of the item, as they appear after the UpdateItem operation.

  • UPDATED_NEW - Returns only the updated attributes, as they appear after the UpdateItem operation.

There is no additional cost associated with requesting a return value aside from the small network and processing overhead of receiving a larger response. No read capacity units are consumed.

The values returned are strongly consistent.

ReturnValuesOnConditionCheckFailure
ReturnValuesOnConditionCheckFailure | undefined

An optional parameter that returns the item attributes for an UpdateItem operation that failed a condition check.

There is no additional cost associated with requesting a return value aside from the small network and processing overhead of receiving a larger response. No read capacity units are consumed.

UpdateExpression
string | undefined

An expression that defines one or more attributes to be updated, the action to be performed on them, and new values for them.

The following action values are available for UpdateExpression.

  • SET - Adds one or more attributes and values to an item. If any of these attributes already exist, they are replaced by the new values. You can also use SET to add or subtract from an attribute that is of type Number. For example: SET myNum = myNum + :val

    SET supports the following functions:

    • if_not_exists (path, operand) - if the item does not contain an attribute at the specified path, then if_not_exists evaluates to operand; otherwise, it evaluates to path. You can use this function to avoid overwriting an attribute that may already be present in the item.

    • list_append (operand, operand) - evaluates to a list with a new element added to it. You can append the new element to the start or the end of the list by reversing the order of the operands.

    These function names are case-sensitive.

  • REMOVE - Removes one or more attributes from an item.

  • ADD - Adds the specified value to the item, if the attribute does not already exist. If the attribute does exist, then the behavior of ADD depends on the data type of the attribute:

    • If the existing attribute is a number, and if Value is also a number, then Value is mathematically added to the existing attribute. If Value is a negative number, then it is subtracted from the existing attribute.

      If you use ADD to increment or decrement a number value for an item that doesn't exist before the update, DynamoDB uses 0 as the initial value.

      Similarly, if you use ADD for an existing item to increment or decrement an attribute value that doesn't exist before the update, DynamoDB uses 0 as the initial value. For example, suppose that the item you want to update doesn't have an attribute named itemcount, but you decide to ADD the number 3 to this attribute anyway. DynamoDB will create the itemcount attribute, set its initial value to 0, and finally add 3 to it. The result will be a new itemcount attribute in the item, with a value of 3.

    • If the existing data type is a set and if Value is also a set, then Value is added to the existing set. For example, if the attribute value is the set [1,2], and the ADD action specified [3], then the final attribute value is [1,2,3]. An error occurs if an ADD action is specified for a set attribute and the attribute type specified does not match the existing set type.

      Both sets must have the same primitive data type. For example, if the existing data type is a set of strings, the Value must also be a set of strings.

    The ADD action only supports Number and set data types. In addition, ADD can only be used on top-level attributes, not nested attributes.

  • DELETE - Deletes an element from a set.

    If a set of values is specified, then those values are subtracted from the old set. For example, if the attribute value was the set [a,b,c] and the DELETE action specifies [a,c], then the final attribute value is [b]. Specifying an empty set is an error.

    The DELETE action only supports set data types. In addition, DELETE can only be used on top-level attributes, not nested attributes.

You can have many actions in a single expression, such as the following: SET a=:value1, b=:value2 DELETE :value3, :value4, :value5

For more information on update expressions, see Modifying Items and Attributes  in the Amazon DynamoDB Developer Guide.

UpdateItemCommand Output

See UpdateItemCommandOutput for details

Parameter
Type
Description
$metadata
Required
ResponseMetadata
Metadata pertaining to this request.
Attributes
Record<string, AttributeValue> | undefined

A map of attribute values as they appear before or after the UpdateItem operation, as determined by the ReturnValues parameter.

The Attributes map is only present if the update was successful and ReturnValues was specified as something other than NONE in the request. Each element represents one attribute.

ConsumedCapacity
ConsumedCapacity | undefined

The capacity units consumed by the UpdateItem operation. The data returned includes the total provisioned throughput consumed, along with statistics for the table and any indexes involved in the operation. ConsumedCapacity is only returned if the ReturnConsumedCapacity parameter was specified. For more information, see Capacity unity consumption for write operations  in the Amazon DynamoDB Developer Guide.

ItemCollectionMetrics
ItemCollectionMetrics | undefined

Information about item collections, if any, that were affected by the UpdateItem operation. ItemCollectionMetrics is only returned if the ReturnItemCollectionMetrics parameter was specified. If the table does not have any local secondary indexes, this information is not returned in the response.

Each ItemCollectionMetrics element consists of:

  • ItemCollectionKey - The partition key value of the item collection. This is the same as the partition key value of the item itself.

  • SizeEstimateRangeGB - An estimate of item collection size, in gigabytes. This value is a two-element array containing a lower bound and an upper bound for the estimate. The estimate includes the size of all the items in the table, plus the size of all attributes projected into all of the local secondary indexes on that table. Use this estimate to measure whether a local secondary index is approaching its size limit.

    The estimate is subject to change over time; therefore, do not rely on the precision or accuracy of the estimate.

Throws

Name
Fault
Details
ConditionalCheckFailedException
client

A condition specified in the operation failed to be evaluated.

InternalServerError
server

An error occurred on the server side.

InvalidEndpointException
client
ItemCollectionSizeLimitExceededException
client

An item collection is too large. This exception is only returned for tables that have one or more local secondary indexes.

ProvisionedThroughputExceededException
client

Your request rate is too high. The Amazon Web Services SDKs for DynamoDB automatically retry requests that receive this exception. Your request is eventually successful, unless your retry queue is too large to finish. Reduce the frequency of requests and use exponential backoff. For more information, go to Error Retries and Exponential Backoff  in the Amazon DynamoDB Developer Guide.

ReplicatedWriteConflictException
client

The request was rejected because one or more items in the request are being modified by a request in another Region.

RequestLimitExceeded
client

Throughput exceeds the current throughput quota for your account. Please contact Amazon Web ServicesSupport  to request a quota increase.

ResourceNotFoundException
client

The operation tried to access a nonexistent table or index. The resource might not be specified correctly, or its status might not be ACTIVE.

TransactionConflictException
client

Operation was rejected because there is an ongoing transaction for the item.

DynamoDBServiceException
Base exception class for all service exceptions from DynamoDB service.