Hands-On Software Architecture with Golang

Mutations

Besides retrieving data, APIs also need to support changes or mutations to the data. There generally are three kinds of mutations:

• Creation of new data
• Update for existing data
• Deletion of data

Mutations follow the general structure of queries:

mutation { 
  createHotel(name: "Taj", noRooms: 30) { 
    id 
  } 
} 

Here the mutation has a createHotel root field, and it identifies the mutation uniquely. We are giving it the name and noRooms parameters, with the Taj and 30 values respectively. Like a query, the payload here describes what we want in terms of the properties of the newly created object; here we are asking for the ID of the new person.

Continuing with our hotel example in graphql-go, the mutation root object defines all the various ...