get row by partition key on aws dynamodb-CodePudding

I'm trying to return a a row with id (partition key)

  var db = new AWS.DynamoDB.DocumentClient();
  const id = "123";
  var queryParams = {
    TableName: "students",
    IndexName: "id",
    KeyConditionExpression: "id = :id",
    ExpressionAttributeValues: {
      ":id": id,
    },
  };

  const query = db.query(queryParams).promise();

but is throwing this error:

ValidationException: 1 validation error detected: Value 'id' at 'indexName' failed to satisfy constraint: Member must have length greater than or equal to 3

isn't partition key enough to get a record? I'm confused partition key is not the same as index name?

I also tried with

  var db = new AWS.DynamoDB.DocumentClient();
  var queryParams = {
    TableName: "students",
    Key: {
      id: "123",
    },
  };

  const query = db.get(queryParams).promise();

and it doesn't return anything

CodePudding user response：

You don't actually have an index named id. You don't need to provide an index when querying on the partition key. Simply remove this line:

IndexName: "id",

Also, note that both table and index names must be 3-255 characters in length (inclusive), which explains the error message that you see.

The following code (both query and get) works fine for me:

const AWS = require('aws-sdk');
AWS.config.update({ region: 'us-east-1' });
const db = new AWS.DynamoDB.DocumentClient();

const ID = "123";
const TABLE_NAME = "students";

const getParams = {
  TableName: TABLE_NAME,
  Key: {
    id: ID,
  },
};

const queryParams = {
  TableName: TABLE_NAME,
  KeyConditionExpression: "id = :id",
  ExpressionAttributeValues: {
    ":id": ID,
  },
};

(async () => {
  const rc1 = await db.get(getParams).promise();
  console.log('get rc:', rc1);

  const rc2 = await db.query(queryParams).promise();
  console.log('query rc:', rc2);
})();