updating a JSON array in AWS dynamoDB

Question

My document looks like this:

{
  \"data\": {
      \"eventId\": \"20161029125458-df-d\",
      \"name\": \"first\",
      \"purpose\": \"test\",
      \"loca         


        

Answer 1

An example of an update query:

Data structure (saved in DynamoDB)

{
  tenant_id: 'tenant_1',
  users: {
    user1: {
      _id: 'user1',
      email_address: 'test_email_1@gmail.com'
    },
    user2: {
      _id: 'user2',
      email_address: 'test_email_2@gmail.com'
    }
  }
}

Data for update (used in the params)

var user = {
 email_address: 'updated@gmail.com'
}

Params

var params = {
    TableName: 'tenant-Master',
    Key: {
       "tenant_id": 'tenant_1'
    },
    UpdateExpression: "set #users.user1 = :value",
    ExpressionAttributeNames: {
    "#users": "users"
    },
    ExpressionAttributeValues: {
    ":value": user,
    },
 };

Explanation

By switching to a map of maps from an array of maps we can now use UpdateExpression: "set #users.user1 = :value" to update our nested object at the map of users with the id of user1.

NOTE: This method as is will REPLACE the entire map object at users.user1. Some changes will need to be made if you want to keep pre-existing data.