Mutations

What Is A Mutation

Simply mutations are just like queries but they can cause a data write, Technically Queries can be used to write data too however it’s not suggested to use it. So mutations are like queries, they have names, parameters and they can return data.

A Simple Mutation

Let’s try to implement the createLink mutation, since we do not have a database set up yet(we’ll get it done in the next section) we just receive the link data and construct a link object and send it back for response!

This function receives a NewLink with type of input we defined NewLink structure in our schema.graphql.

now run server and use the mutation to create a new link:

mutation {
  createLink(input: {title: "new link", address:"http://address.org"}){
    title,
    user{
      name
    }
    address
  }
}

and you will get:

{
  "data": {
    "createLink": {
      "title": "new link",
      "user": {
        "name": "test"
      },
      "address": "http://address.org"
    }
  }
}

Nice now we know what are mutations and queries we can setup our database and make these implementations more practical.

Next Chapter

Database

Setup mysql db with migrations in golang

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