Basics
GraphQL Mutations
Writing GraphQL Mutations
GraphQL mutations modify server data with input types.
Introduction to GraphQL Mutations
GraphQL mutations are used to modify server-side data. Unlike queries, which only fetch data, mutations allow you to create, update, or delete data on the server. Each mutation operation can have an optional input type, which specifies the structure of the data that the mutation will accept.
Defining a Mutation in GraphQL
To define a mutation in GraphQL, you need to specify it in your schema. A mutation can take arguments, which are used to pass the data that needs to be modified. Here's how you might define a simple mutation to create a new user:
Executing a Mutation
Executing a mutation is similar to executing a query. You specify the mutation along with any arguments it requires. Here’s an example of how you might execute the createUser mutation:
Using Input Types in Mutations
GraphQL allows you to define input types to ensure that mutations receive the correct data structure. Input types are defined similarly to object types, but they are only used for input data. Here’s an example:
Handling Mutation Responses
Mutations can return data, just like queries. This is useful for confirming the result of the mutation or fetching updated data. For example, the createUser mutation returns the new user's details:
Conclusion
GraphQL mutations are a powerful way to modify data on the server. By using input types, you can enforce the structure of data passed to mutations, ensuring data integrity and reducing errors. In the next post, we will explore how to use variables to make your GraphQL operations even more dynamic and flexible.
