What kind of operations could GraphQL schema have?

A GraphQL schema can have three main types of operations: queries, mutations, and subscriptions.

1. Queries:

   • Queries are used to read or fetch data from the server. They allow clients to request specific data and receive exactly what they ask for, making data retrieval efficient and precise. For example, a query might request a list of books with their titles and authors[1][3][8][9][13].

2. Mutations:

   • Mutations are used to modify data on the server. This includes creating, updating, or deleting data. Each mutation operation specifies the changes to be made and can return the modified data. For instance, a mutation might add a new author or update the details of an existing book[1][8][9][13].

3. Subscriptions:

   • Subscriptions are used to listen for real-time updates from the server. They allow clients to receive live data updates whenever specific events occur on the server. Subscriptions are typically implemented using WebSockets to provide a continuous stream of data. For example, a subscription might notify clients whenever a new book is added to the database[1][8][9][13].

These operations are defined in the...