CODEWITHSUNDEEP
amazon-web-serviceslambdaaws-lambdaamazon-dynamodbdynamodb-queries
Hina Patidar
Hina Patidar

Reputation: 11

Update dynamoDB column using condition expression

I want to update existing item of dynamoDB table using condition equivalent to like (%) condition of sql

opIdUserId status

opIdUserId in my dynamodb is Primary partition key. I want to update status to COMP for opIdUserId field value starting from or contains 123.

this is what I am trying currently but researched and found I can not use KeyConditionExpression for update.

const AWS = require('aws-sdk'); 
 const docClient = new AWS.DynamoDB.DocumentClient({region: 'eu-west-1'}); 
 var table = "tablename";

exports.handler = function(event, context, callback){
    var params = {
    TableName: table,

    KeyConditionExpression: "begins_with(opIdUserId, :i)",
    UpdateExpression: "set operationStatus = :o",
    ExpressionAttributeValues:{
        ":o":"COMP",
        ":i":"123-"
    },
    ReturnValues:"UPDATED_NEW"
};
docClient.update(params, function(err, data) {
    if (err) {

         callback(err, null);
    } else {
         callback(null,data); 

    }
});
 }

Please suggest how I can update my item in dynamoDB with specific condition.

Upvotes: 0

Views: 1690

Answers (1)

guzmonne
guzmonne

Reputation: 2540

You should create a Global Secondary Index on your table to query for the items that start with 123 using a KeyConditionExpression. 

var params = {
  TableName: table,
  KeyConditionExpression: "id = :id AND begins_with(opIdUserId, :opIdUserId)",
  UpdateExpression: "set operationStatus = :operationStatus",
  ExpressionAttributeValues:{
    ":opIdUserId":"123-",
    ":id": "something"
  }
};

var documentClient = new AWS.DynamoDB.DocumentClient();

documentClient.query(params, function(err, data) {
   if (err) console.log(err);
   else console.log(data);
});

Bare in mind that you can't run a query using BEGINS_WITH on a partition key, only on a sort key.

Then, you can use the update method over every individual element using the partition and sort key for the table, updating the operationStatus.

If you provide me with information regarding your DynamoDB table, I could help you create the GSI.

Upvotes: 1

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