GraphQL API Mutation Examples

Understanding Mutations in GraphQL API

GraphQL is a powerful query language for APIs that allows clients to request only the data they need. One of its key features is the ability to perform mutations, which enable clients to modify server-side data. Mutations are essential for creating, updating, or deleting data, making them a core part of any interactive application. Below are three practical examples of mutations in a GraphQL API that demonstrate how to effectively use them in different contexts.

Example 1: Creating a New User

Use Case

In a web application where users can sign up, a mutation is required to create a new user in the database.

mutation {
  createUser(input: {
    username: "new_user",
    email: "new_user@example.com",
    password: "securePassword123"
  }) {
    id
    username
    email
  }
}

This mutation, createUser, takes an input object containing the user’s username, email, and password. Upon successful execution, it returns the newly created user’s id, username, and email.

Notes:

• Ensure that the password is handled securely and hashed before storing it in the database.
• Consider implementing validation rules for the input fields to enhance data integrity.

Example 2: Updating an Existing Product

Use Case

In an e-commerce application, you may need to update product details. This mutation allows administrators to change product information.

mutation {
  updateProduct(id: "12345", input: {
    name: "Updated Product Name",
    price: 19.99,
    description: "This is the updated description of the product."
  }) {
    id
    name
    price
    description
  }
}

Here, the updateProduct mutation requires the product’s id and an input object containing the new name, price, and description. The response includes the updated product details.

Notes:

• Make sure to check whether the product exists before attempting the update to avoid errors.
• You can also implement version control on product data to manage changes more effectively.

Example 3: Deleting a Comment

Use Case

In a blogging platform, users should be able to delete their comments. This mutation enables users to remove a comment by its ID.

mutation {
  deleteComment(id: "abc123") {
    success
    message
  }
}

The deleteComment mutation takes the id of the comment to be deleted and returns an object indicating whether the operation was successful along with a message.

Notes:

• Implement access control to ensure that only the original commenter can delete their comment.
• Consider providing a soft delete option to preserve data integrity for auditing purposes.

By implementing these examples of mutation in GraphQL API, developers can effectively manage and modify data within their applications, allowing for a dynamic and responsive user experience.