eolas/zk/DynamoDB SDK commands.md

id	title	tags	created
8b6h	DynamoDB SDK commands	AWS databases dynamodb	Sunday, June 23, 2024

DynamoDB SDK commands

The following commands are for using @aws-sdk/client-dynamodb (the JS SDK).

Create client

import DynamoDBClient from "@aws-sdk/client-dynamodb";

const client = new DynamoDBClient({
  region: "eu-west-2",
  accessKeyId: process.env.ACCESS_KEY_ID,
  secretAccessKey: process.env.ACCESS_KEY_ID,
});

DynamoDB Document Client

The Document Client returns the data as a standard JSON document in the manner of a document-based NoSQL database. Without it, DynamoDB will return the data with type data which is unwieldy and hard to parse.

To transform into a document structure:

import DynamoDBClient from "@aws-sdk/client-dynamodb";
import DynamoDBDocumentClient from "@aws-sdk/lib-dynamodb";

const client = new DynamoDBClient({
  region: "eu-west-2",
  accessKeyId: process.env.ACCESS_KEY_ID,
  secretAccessKey: process.env.ACCESS_KEY_ID,
});

const dynamoDbDocumentClient = DynamoDBDocumentClient.from(client);

Query a table

Querying is the most performant and cost-effective method since it is an O(1) lookup against a partition key or secondary index.

const params = {
  TableName: "YourTableName",
  KeyConditionExpression: "#pk = :pk",
  ExpressionAttributeNames: { "#pk": "PrimaryKeyAttributeName" },
  ExpressionAttributeValues: { ":pk": "PrimaryKeyValue" },
};

Scan a table

Scanning is less performant (O(n)) and most expensive since it requires checking every item in the database.

Related notes