transactWrite

Introduction

transactWrite method performs transact write request using aws-sdk TransactWriteItemsCommand.

execute

transactWrite takes 2 arguments:

1. (required) an object which must include:
   • check and/or update and/or put and/or delete
2. (optionnal) options

check

an array of Condition expression with at least item identifier.

const res = await User.transactWrite({
  check: [
    {
      id: "user-64",
      isActive: false,
    },
  ],
});

delete

an array of object which includes

• condition Condition expression object with at least item identifier.
• (optionnally) ReturnValuesOnConditionCheckFailure.

const res = await User.transactWrite({
  delete: [
    {
      condition: {
        id: "user-64",
        isActive: false,
      },
    },
  ],
});

put

an array of object which includes

• item item to be stored.
• (optionnally) condition Condition expression object.
• (optionnally) setterInfo
• (optionnally) ReturnValuesOnConditionCheckFailure.

const res = await User.transactWrite({
  put: [
    {
      item: {
        id: "user-64",
        firstname: "John",
        lastname: "Doe",
        age: 27,
        isActive: true,
      },
      condition: {
        age: {
          $gt: 25,
        },
      },
      setterInfo: {
        generateHash: true,
      },
    },
  ],
});

update

an array of object which includes

• condition Condition expression object with at least item identifier.
• set any Update Expression object.
• (optionnally) ReturnValuesOnConditionCheckFailure.

const res = await User.transactWrite({
  update: [
    {
      condition: {
        id: "user-64",
        isActive: false,
      },
      set: {
        firstname: "John",
      },
    },
  ],
});

All together

const res = await User.transactWrite({
  check: [
    {
      id: "user-07",
      isActive: false,
    },
    {
      id: "user-91",
      isActive: true,
    },
  ],
  put: [
    {
      item: {
        id: "user-61",
        firstname: "John",
        lastname: "Doe",
        age: 25,
        isActive: true,
      },
      condition: {
        age: {
          $gt: 25,
        },
      },
      setterInfo: {
        generateHash: true,
      },
    },
  ],
  delete: [
    {
      condition: {
        id: "user-32",
        isActive: false,
      },
    },
  ],
  update: [
    {
      condition: {
        id: "user-12",
        isActive: false,
      },
      set: {
        firstname: "Mike",
      },
    },
  ],
});

options

options is an object which accepts TransactWriteItemsCommandInput options and DynamoQL specific options.

exec

exec boolean directive to execute or not the actual request.
When false transactWrite will return TransactWriteItemsCommandInput object.

import type { TransactWriteItemsCommandInput } from "@aws-sdk/client-dynamodb";

const cmd: TransactWriteItemsCommandInput = await User.transactWrite(
  {
    check: [
      {
        id: "user-07",
        isActive: true,
      },
    ],
    update: [
      {
        condition: {
          id: "user-12",
          isActive: false,
        },
        set: {
          friendsId: {
            $push: "user-07",
          },
        },
      },
    ],
  },
  {
    exec: false,
  }
);