AWS AppSync GraphQL : DynamoDB ConditionalCheckFailedException when updating object in mutation

Question

I'm modeling a User object with graphql for a react native app using amplify and appsync. I need to update the name field after creating the User but I am getting a DynamoDB: ConditionalCheckFailedException. Creating users and querying the User table works fine, I just can't update the fields of the existing object.

I am defining the User type within my project directory (amplify/backend/api/schema.graphql) and letting the amplify CLI generate GraphQL statements (queries, mutations and subscription) based on my schema types.

The schema I'm using:

type User @model @auth(rules: [{allow: owner}]) {
   username: String!
   name: String
}


type Mutation {
    createUser(input: CreateUserInput!, condition: ModelUserConditionInput): User
    updateUser(input: UpdateUserInput!, condition: ModelUserConditionInput): User
    deleteUser(input: DeleteUserInput!, condition: ModelUserConditionInput): User
}

input UpdateUserInput {
    username: String
    name: String
}

I run a mutation to create a User with the credentials of the logged-in user. From the AppSync console, I log in as the Cognito user with same username (745ab477-5702-4f8d-b938-a987a3d9d192) and run this mutation:

mutation updateUser{
    updateUser(input: {
      name: "James"
    }
    condition:{
      username: {eq: "745ab477-5702-4f8d-b938-a987a3d9d192"}
    }){
    username
    name
  }
}

Which produces:

  {
  "data": {
    "updateUser": null
  },
  "errors": [
    {
      "path": [
        "updateUser"
      ],
      "data": null,
      "errorType": "DynamoDB:ConditionalCheckFailedException",
      "errorInfo": null,
      "locations": [
        {
          "line": 40,
          "column": 5,
          "sourceName": null
        }
      ],
      "message": "The conditional request failed (Service: AmazonDynamoDBv2; Status Code: 400; Error Code: ConditionalCheckFailedException; Request ID: HND4VSCK8HLM5NC08VDEV51CORVV4KQNSO5AEMVJF66Q9ASUAAJG)"
    }
  ]
}

This is the DynamoDB User table after adding the current user:

Alex Alex · Accepted Answer · 2020-01-16T08:25:53

You should specify the primary key in your schema

type User @model @auth(rules: [{allow: owner}]) {
   id:ID!,
   username: String!
   name: String
}

and change your request like below

  mutation updateSampleUser{
      updateSampleUser(
               input:{name:"James",id:"9f4...."}
              )
         {
           name
         }
    }

It is equivalent to the following SQL statement

 update tbl1 set name = "James" where  id = "9f4...."

and with @auth(rules: [{allow: owner}]) just owner can do update.

AWS AppSync GraphQL : DynamoDB ConditionalCheckFailedException when updating object in mutation

1 Answers