CODEWITHSUNDEEP
javascriptamazon-web-servicesamazon-dynamodb
krackoder
krackoder

Reputation: 2981

Adding a new key-value to a map in Dynamo DB in JavaScript

I have an item in a dynamodb table that has a key of type map. The name of the key is mykey and the map stored in the key is:

{ 
   name: something
   address: somewhere
}

I want to add a new item to this map data. Let's say for example, color. The updated map should look like this:

{ 
   name: something
   address: somewhere
   color: red
}

I am using JavaScript SDK but I'm unable to figure out how to go about this. After reading documentation, I think I need to use list_append in updateItem function but I am not able to figure out how.

I do not want to read data, add the new key-value, and write back. This will create a 'read before write' concurrency problem as I have multiple processes trying to update the map.

Upvotes: 1

Views: 1093

Answers (1)

Max
Max

Reputation: 15955

You need to use the updateItem API. I don't have a specific example in JavaScript, but the basic idea is this:

var params = {
  Key: {
    KeyName: {
      S: "KeyValue"
    }
  },
  TableName: "TheTableName",
  AttributeUpdates: {
    color: {
      Action: "ADD",
      Value: {
        S: "red"
      }
    }
  }
};

client.updateItem(params, callback);

Upvotes: 2

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