Batch Operations - DynamoDB CRUD Operations

Batch operations are used for performing multiple operations on multiple items in a single request in DynamoDB. This makes it possible to reduce the number of round-trips between an application and a DynamoDB table. The following are the CRUD operations that can be performed using batch operations:

Syntax

The syntax for batch operations is as follows:

{
  "RequestItems": {
    "TableName": [
      {
        "PutRequest": {
          "Item": {
            "attribute_name": { "data_type": value },
            /* more attributes */
          }
        }
      },
      {
        "DeleteRequest": {
          "Key": {
            "attribute_name": { "data_type": value },
            /* more keys */
          }
        }
      },
      {
        "UpdateRequest": {
          "Key": {
            "attribute_name": { "data_type": value },
            /* more keys */
          },
          "UpdateExpression": "set attribute_name=:value",
          "ExpressionAttributeValues": {
            ":value": { "data_type": value },
            /* more values */
          }
        }
      },
      /* more put, delete, or update requests */
    ]
  }
}

Example

The following example illustrates how to use batch operations to perform multiple CRUD operations:

{
  "RequestItems": {
    "Table": [
      {
        "PutRequest": {
          "Item": {
            "id": { "S": "1" },
            "name": { "S": "John Doe" },
            "age": { "N": "35" },
            "gender": { "S": "Male" }
          }
        }
      },
      {
        "UpdateRequest": {
          "Key": {
            "id": { "S": "2" }
          },
          "UpdateExpression": "set #n=:new_name",
          "ExpressionAttributeNames": { "#n": "name" },
          "ExpressionAttributeValues": { ":new_name": { "S": "Jane Doe" } }
        }
      },
      {
        "DeleteRequest": {
          "Key": {
            "id": { "S": "3" }
          }
        }
      }
    ]
  }
}

Output

The output of the above example is:

{
  "UnprocessedItems": {}
}

Explanation

In the above example, we performed three operations on the Table table. We inserted a new item, updated an item with id equal to 2, and deleted an item with id equal to 3. The UnprocessedItems attribute is returned if there are any items that were not processed due to exceeded provisioned throughput for the table or a failure to satisfy the business logic of the request.

Use

Batch operations are useful when you want to perform multiple CRUD operations in a single request. This can reduce the number of round-trips between the application and the table and improve the performance and efficiency of the application.

Important Points

• Maximum of 25 items can be processed in a single batch request.
• You can perform both put and delete operations in a single batch.
• Batch operations do not support conditional expressions.
• Batch operations can span multiple tables in a single request.
• You can use the TransactWriteItems API for ACID-compliant transactions on multiple tables.

Summary

Batch operations are used to perform multiple CRUD operations on multiple items in a single request in DynamoDB. This reduces the number of round-trips between an application and a table, improving performance and efficiency. You can perform up to 25 items in a single batch request, combine both put and delete operations, and span multiple tables in a single request if necessary.