Mutations
=========
GraphQL mutations are used to modify server-side data (i.e. write, update or delete data). As with queries, mutation
fields are auto-generated based on the Postgres schema. Here’s a sample mutation field from our reference
author/article schema:

.. code-block:: graphql

  insert_article (
    objects: [article_insert_input!]!
    on_conflict: article_on_conflict
  ): article_mutation_response

  # response of any mutation on the table "article"
  type article_mutation_response {
    # number of affected rows by the mutation
    affected_rows: Int!
    #data of the affected rows by the mutation
    returning: [author!]!
  }

As you can see from the schema, you can:

#. Pass multiple objects to the mutation.
#. Return objects (with nested objects) from the affected rows in the response.

Let's use this reference author/article schema to look at different types of mutations.

.. toctree::
  :maxdepth: 1

  Insert <insert>
  Upsert <upsert>
  Update <update>
  Delete <delete>
  multiple-mutations