Contract Based Schema
In GraphQL Schema is like a blueprint that specifies how your data will be and what operations the client can perform. It defines what actions and operations a client can perform to fetch particular data.
A contract in GraphQL is like an agreement between the Client and the server. The client asks for data and the server provides the data.
Now, when developing an app it is important to tell other developers or let other developers know what data your GraphQL server is going to provide and what kind of queries it will accept. This will help you and other developers to make queries specifying what kind of data they need. This is called contract-based approach.
Here’s an example of contract based schema:
type book {
id: ID!
title: String!
author: User!
}
type ReaderID {
id: ID!
name: String!
email: String!
}
type Query {
getAllBooks: [book!]!
getBookById(id: ID!): book!
}
In the above schema we have defined three main types :
- Book
- ReaderID
- Query
Book Type :
In the schema we have defined what fields does the Book type have. It has id, title, and author.
ReaderID Type :
ReaderID type represents ReaderID object that have three fields – id, name, and string.
Query Type :
Query type represents query objects and have two fields – getAllBooks, and getBooksById.
Why Use GraphQL?
GraphQL is the query language for the Application Programming Interfaces (APIs). It provides a complete description in your API so that the necessary information will get fetched. It provides power to clients to ask for exactly what they need and nothing more.
In this article, we are going to look at how GraphQL is different from others such as REST, SOAP, and GRPC. These are some well-known and most-used API developing frameworks that most developers use. We will compare and look at why GraphQL stands above these frameworks and why GraphQL is the future for developing APIs.