CODEWITHSUNDEEP
javascriptjsonnode.jsamazon-dynamodbaws-sdk
Abdul Manaf
Abdul Manaf

Reputation: 5003

Unable to update array aws Dynamo

iam trying to update json array.i have a table in dynamoDb.i successfully inserted the json data to dynamo using put method.

Partition key : _id , Type : S

This is my json data saved into the database. 

{
    "_id": "001",
    "email": "[email protected]",
    "class": {
        "student_list": []
    }
}

But i cant updated json array student_list using key email. I have following code

var AWS = require("aws-sdk");
var docClient = new AWS.DynamoDB.DocumentClient();

var params = {
    TableName: "testTable1",
    Key: {
        "email": "[email protected]",
    },
    UpdateExpression: "set class.student_list = list_append (class.student_list, :studentEmail)",
    ExpressionAttributeValues: {
        ":studentEmail": "[email protected]"
    },
    ReturnValues: "UPDATED_NEW"
};

docClient.update(params, function (err, data) {
    if (err) {
        console.error("Unable to update item. Error JSON:", JSON.stringify(err, null, 2));
    } else {
        console.log("UpdateItem succeeded:", JSON.stringify(data, null, 2));
    }
});

But i got an error message like this

Unable to update item. Error JSON: {
  "message": "Invalid UpdateExpression: Incorrect operand type for operator or function; operator or function: list_append, operand type: S",
  "code": "ValidationException",
  "time": "2016-07-18T14:31:44.978Z",
  "requestId": "378NSB5RVB1TNI0PB1Q3OH67V3VV4KQNSO5AEMVJF66Q9ASUAAJG",
  "statusCode": 400,
  "retryable": false,
  "retryDelay": 0
}

What is the actual issue related with this?

Upvotes: 3

Views: 760

Answers (1)

Conti
Conti

Reputation: 1273

From the docs: http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.Modifying.html

Operand type must be contained in a list.

"The new element must be contained in a list, for example to add 2 to a list, the operand would be [2]"

Upvotes: 1

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