4.2: Query

The Query API action lets you retrieve multiple items with the same partition key. You can use the Query API to easily fetch all related objects in a one-to-many relationship or a many-to-many relationship.

You can use the Query operation on either your base table or a secondary index. When making a Query, you must include a partition key in your request.

Refer the code below: This is a high level overview of using the AWS SDK and the DynamoDB Client to get all the messages from the table.

            import { QueryCommand } from "@aws-sdk/lib-dynamodb";
            import ddbDocClient from "@/lib/clients/dynamoDBClient";
            import { dbName } from "@/lib/constants";

            const dbCommand = new QueryCommand({
                  TableName: dbName,
                  KeyConditionExpression: "#pk_key = :pk_value",
                  ExpressionAttributeNames: {
                      "#pk_key": "pk",
                  },
                  ExpressionAttributeValues: {
                      ":pk_value": "message",
                  },
            });

            const dbResponse = await ddbDocClient.send(dbCommand);
          

The Query would return all the messages that you have added earlier. The Query operation is how you efficiently read items in an item collection.

You can also query a secondary index, just add the IndexName property to the QueryCommand.