javascript - How to use DynamoDB batchGet command - Stack Overflow

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I created a "Movie" DynamoDB table from AWS DynamoDB tutorial posted at

.Js.01.html

with the attribute below:

    var tableAttrs = {
        TableName : "Movies",
        KeySchema: [
            { AttributeName: "year", KeyType: "HASH"},
            { AttributeName: "title", KeyType: "RANGE" }
        ],
        AttributeDefinitions: [
            { AttributeName: "year", AttributeType: "N" },
            { AttributeName: "title", AttributeType: "S" }
        ],
        ProvisionedThroughput: {
            ReadCapacityUnits: 5,
            WriteCapacityUnits: 5
        }
    };

Now I want to use the batchGet mand:

var params = {
  "RequestItems" : {
      "Movies": {
        "Keys" : [
          {year : { "N" : "1000" } },
          {year : { "N" : "1001" } }
        ]
      }
    }
}

And running it with:

let db = new DynamoDB.DocumentClient({ apiVersion: '2012-08-10' })

let result = db.batchGet(params).promise();

But I am getting the error:

ValidationException: The provided key element does not match the schema

Why does the provided year as a key element does not match the schema? How to avoid this error and make it work?

Below is the screenshot showing the table keys:

I created a "Movie" DynamoDB table from AWS DynamoDB tutorial posted at

https://docs.aws.amazon./amazondynamodb/latest/developerguide/GettingStarted.Js.01.html

with the attribute below:

    var tableAttrs = {
        TableName : "Movies",
        KeySchema: [
            { AttributeName: "year", KeyType: "HASH"},
            { AttributeName: "title", KeyType: "RANGE" }
        ],
        AttributeDefinitions: [
            { AttributeName: "year", AttributeType: "N" },
            { AttributeName: "title", AttributeType: "S" }
        ],
        ProvisionedThroughput: {
            ReadCapacityUnits: 5,
            WriteCapacityUnits: 5
        }
    };

Now I want to use the batchGet mand:

var params = {
  "RequestItems" : {
      "Movies": {
        "Keys" : [
          {year : { "N" : "1000" } },
          {year : { "N" : "1001" } }
        ]
      }
    }
}

And running it with:

let db = new DynamoDB.DocumentClient({ apiVersion: '2012-08-10' })

let result = db.batchGet(params).promise();

But I am getting the error:

ValidationException: The provided key element does not match the schema

Why does the provided year as a key element does not match the schema? How to avoid this error and make it work?

Below is the screenshot showing the table keys:

• javascript
• typescript
• amazon-web-services
• amazon-dynamodb
• dynamodb-queries

Share Improve this question Follow edited Apr 23, 2021 at 21:36 alphanumeric asked Apr 23, 2021 at 19:51 alphanumericalphanumeric 19.4k7474 gold badges277277 silver badges422422 bronze badges

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1 Answer 1

Sorted by: Reset to default 5

BatchGetItem : From the Docs

The BatchGetItem operation returns the attributes of one or more items from one or more tables. You identify requested items by primary key.

We must specify entire primary key i.e bination of partition key and sort key. Same with GetItem too.

Batch Get:

const AWS = require("aws-sdk");
AWS.config.update({ region: "us-east-1" });
var documentClient = new AWS.DynamoDB.DocumentClient();
documentClient.batchGet(
  {
    RequestItems: {
      Movies: {
        Keys: [
          { year: 1000, title: "one" },
          { year: 1000, title: "two" },
        ],
      },
    },
  },
  function (err, data) {
    console.log("err", err, "data", JSON.stringify(data));
  }
);

To get by records only by Partition Key, we can use query.

Query:

const AWS = require("aws-sdk");
AWS.config.update({ region: "us-east-1" });
var documentClient = new AWS.DynamoDB.DocumentClient();
documentClient.query(
  {
    TableName: "Movies",
    KeyConditionExpression: "#year = :yearValue ",
    ExpressionAttributeValues: {
      ":yearValue": 1000,
    },
    ExpressionAttributeNames: {
      "#year": "year",
    },
  },
  function (err, data) {
    if (err) console.error(err);
    else
      console.log("dynamodb query succeeded:", JSON.stringify(data, null, 2));
  }
);

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