name : transact-write-items.rst **Example 1: To write items atomically to one or more tables** The following ``transact-write-items`` example updates one item and deletes another. The operation fails if either operation fails, or if either item contains a ``Rating`` attribute. :: aws dynamodb transact-write-items \ --transact-items file://transact-items.json \ --return-consumed-capacity TOTAL \ --return-item-collection-metrics SIZE Contents of the ``transact-items.json`` file:: [ { "Update": { "Key": { "Artist": {"S": "Acme Band"}, "SongTitle": {"S": "Happy Day"} }, "UpdateExpression": "SET AlbumTitle = :newval", "ExpressionAttributeValues": { ":newval": {"S": "Updated Album Title"} }, "TableName": "MusicCollection", "ConditionExpression": "attribute_not_exists(Rating)" } }, { "Delete": { "Key": { "Artist": {"S": "No One You Know"}, "SongTitle": {"S": "Call Me Today"} }, "TableName": "MusicCollection", "ConditionExpression": "attribute_not_exists(Rating)" } } ] Output:: { "ConsumedCapacity": [ { "TableName": "MusicCollection", "CapacityUnits": 10.0, "WriteCapacityUnits": 10.0 } ], "ItemCollectionMetrics": { "MusicCollection": [ { "ItemCollectionKey": { "Artist": { "S": "No One You Know" } }, "SizeEstimateRangeGB": [ 0.0, 1.0 ] }, { "ItemCollectionKey": { "Artist": { "S": "Acme Band" } }, "SizeEstimateRangeGB": [ 0.0, 1.0 ] } ] } } For more information, see `Managing Complex Workflows with DynamoDB Transactions <https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/transactions.html>`__ in the *Amazon DynamoDB Developer Guide*. **Example 2: To write items atomically using a client request token** The following command uses a client request token to make the call to ``transact-write-items`` idempotent, meaning that multiple calls have the same effect as one single call. :: aws dynamodb transact-write-items \ --transact-items file://transact-items.json \ --client-request-token abc123 Contents of the ``transact-items.json`` file:: [ { "Update": { "Key": { "Artist": {"S": "Acme Band"}, "SongTitle": {"S": "Happy Day"} }, "UpdateExpression": "SET AlbumTitle = :newval", "ExpressionAttributeValues": { ":newval": {"S": "Updated Album Title"} }, "TableName": "MusicCollection", "ConditionExpression": "attribute_not_exists(Rating)" } }, { "Delete": { "Key": { "Artist": {"S": "No One You Know"}, "SongTitle": {"S": "Call Me Today"} }, "TableName": "MusicCollection", "ConditionExpression": "attribute_not_exists(Rating)" } } ] This command produces no output. For more information, see `Managing Complex Workflows with DynamoDB Transactions <https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/transactions.html>`__ in the *Amazon DynamoDB Developer Guide*.