AWS SDK v3 DynamoDB Examples

This repository contains examples of using the AWS JavaScript SDK v3 with DynamoDB, focusing on scenarios related to the ConditionExpression attribute. The examples cover the following operations:

1. putItem: Records will be overwritten by default.

2. putItem with ConditionExpression: Prevents overwrites by specifying a condition.

3. updateItem: Updates a record or inserts it if it doesn't exist.

4. updateItem with ConditionExpression: Avoids insertion if the record doesn't exist by using a condition.

Prerequisites

Before running the examples, ensure you have the following prerequisites:

• Node.js installed
• AWS SDK v3 for JavaScript installed

npm install

Configuration

Make sure to configure your AWS credentials using the AWS CLI or by setting environment variables.

export AWS_ACCESS_KEY_ID=your_access_key_id
export AWS_SECRET_ACCESS_KEY=your_secret_access_key
export AWS_REGION=your_region

Examples

1. putItem

The putItem example demonstrates how to add items to DynamoDB, overwriting existing records by default.

2. putItem with ConditionExpression

In this example, putItemWithCondition, a ConditionExpression is used to prevent overwriting existing records. The item will only be added if the specified condition is met.

3. updateItem

The updateItem example showcases updating existing records in DynamoDB. If the record doesn't exist, a new one will be created.

4. updateItem with ConditionExpression

This example, updateItemWithCondition, demonstrates using a ConditionExpression with updateItem to avoid inserting a new record if the one we wanted to update doesn't exist.

Additionally, this example also covers how to write DynamoDB Expressions to access nested objects and expect a `ConditionalCheckFailedException`` to analyze the current values of the record and understand why it failed.

Running the Examples

Execute each example by running the corresponding JavaScript file.

node ./samples/putItem.js
node ./samples/putItemWithCondition.js
node ./samples/updateItem.js
node ./samples/updateItemWithCondition.js