Amazon DynamoDB
API Reference

TransactGetItems

TransactGetItems is a synchronous operation that atomically retrieves multiple items from one or more tables (but not from indexes) in a single account and region. A TransactGetItems call can contain up to 10 TransactGetItem objects, each of which contains a Get structure that specifies an item to retrieve from a table in the account and region. A call to TransactGetItems cannot retrieve items from tables in more than one AWS account or region.

DynamoDB rejects the entire TransactGetItems request if any of the following is true:

  • A conflicting operation is in the process of updating an item to be read.

  • There is insufficient provisioned capacity for the transaction to be completed.

  • There is a user error, such as an invalid data format.

Request Syntax

{ "ReturnConsumedCapacity": "string", "TransactItems": [ { "Get": { "ExpressionAttributeNames": { "string" : "string" }, "Key": { "string" : { "B": blob, "BOOL": boolean, "BS": [ blob ], "L": [ "AttributeValue" ], "M": { "string" : "AttributeValue" }, "N": "string", "NS": [ "string" ], "NULL": boolean, "S": "string", "SS": [ "string" ] } }, "ProjectionExpression": "string", "TableName": "string" } } ] }

Request Parameters

The request accepts the following data in JSON format.

Note

In the following list, the required parameters are described first.

TransactItems

An ordered array of up to 10 TransactGetItem objects, each of which contains a Get structure.

Type: Array of TransactGetItem objects

Array Members: Minimum number of 1 item. Maximum number of 10 items.

Required: Yes

ReturnConsumedCapacity

A value of TOTAL causes consumed capacity information to be returned, and a value of NONE prevents that information from being returned. No other value is valid.

Type: String

Valid Values: INDEXES | TOTAL | NONE

Required: No

Response Syntax

{ "ConsumedCapacity": [ { "CapacityUnits": number, "GlobalSecondaryIndexes": { "string" : { "CapacityUnits": number, "ReadCapacityUnits": number, "WriteCapacityUnits": number } }, "LocalSecondaryIndexes": { "string" : { "CapacityUnits": number, "ReadCapacityUnits": number, "WriteCapacityUnits": number } }, "ReadCapacityUnits": number, "Table": { "CapacityUnits": number, "ReadCapacityUnits": number, "WriteCapacityUnits": number }, "TableName": "string", "WriteCapacityUnits": number } ], "Responses": [ { "Item": { "string" : { "B": blob, "BOOL": boolean, "BS": [ blob ], "L": [ "AttributeValue" ], "M": { "string" : "AttributeValue" }, "N": "string", "NS": [ "string" ], "NULL": boolean, "S": "string", "SS": [ "string" ] } } } ] }

Response Elements

If the action is successful, the service sends back an HTTP 200 response.

The following data is returned in JSON format by the service.

ConsumedCapacity

If the ReturnConsumedCapacity value was TOTAL, this is an array of ConsumedCapacity objects, one for each table addressed by TransactGetItem objects in the TransactItems parameter. These ConsumedCapacity objects report the read-capacity units consumed by the TransactGetItems call in that table.

Type: Array of ConsumedCapacity objects

Responses

An ordered array of up to 10 ItemResponse objects, each of which corresponds to the TransactGetItem object in the same position in the TransactItems array. Each ItemResponse object contains a Map of the name-value pairs that are the projected attributes of the requested item.

If a requested item could not be retrieved, the corresponding ItemResponse object is Null, or if the requested item has no projected attributes, the corresponding ItemResponse object is an empty Map.

Type: Array of ItemResponse objects

Array Members: Minimum number of 1 item. Maximum number of 10 items.

Errors

For information about the errors that are common to all actions, see Common Errors.

InternalServerError

An error occurred on the server side.

HTTP Status Code: 500

ResourceNotFoundException

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

HTTP Status Code: 400

TransactionCanceledException

The entire transaction request was rejected.

DynamoDB rejects a TransactWriteItems request under the following circumstances:

  • A condition in one of the condition expressions is not met.

  • A table in the TransactWriteItems request is in a different account or region.

  • More than one action in the TransactWriteItems operation targets the same item.

  • There is insufficient provisioned capacity for the transaction to be completed.

  • An item size becomes too large (larger than 400 KB), or a local secondary index (LSI) becomes too large, or a similar validation error occurs because of changes made by the transaction.

  • There is a user error, such as an invalid data format.

DynamoDB rejects a TransactGetItems request under the following circumstances:

  • There is an ongoing TransactGetItems operation that conflicts with a concurrent PutItem, UpdateItem, DeleteItem or TransactWriteItems request. In this case the TransactGetItems operation fails with a TransactionCanceledException.

  • A table in the TransactGetItems request is in a different account or region.

  • There is insufficient provisioned capacity for the transaction to be completed.

  • There is a user error, such as an invalid data format.

HTTP Status Code: 400

See Also

For more information about using this API in one of the language-specific AWS SDKs, see the following: