Query variables in GraphQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are query variables in GraphQL?

Query variables are placeholders in a GraphQL query that allow you to pass dynamic values separately from the query text. They help make queries reusable and secure.

beginner

How do you declare a variable in a GraphQL query?

You declare variables inside parentheses after the query name, using a dollar sign ($) followed by the variable name and its type, for example: query GetUser($id: ID!).

intermediate

Why use query variables instead of hardcoding values in GraphQL queries?

Using variables keeps queries clean, reusable, and helps prevent injection attacks by separating data from query structure.

beginner

How do you pass values to query variables when sending a GraphQL request?

You pass a separate JSON object with variable names and their values alongside the query. For example: { "id": "123" }.

intermediate

What does the exclamation mark (!) mean in a variable type like $id: ID!?

The exclamation mark means the variable is non-nullable, so you must provide a value for it when running the query.

How do you indicate a variable in a GraphQL query?

A With a hash (#) before the variable name

B With a dollar sign ($) before the variable name

C With an at sign (@) before the variable name

D With a percent sign (%) before the variable name

GraphQL variables are always indicated by a dollar sign ($) before the variable name.

Where do you declare variables in a GraphQL query?

A At the end of the query

B Inside the query body

C Inside the query name parentheses

D In the HTTP headers

Variables are declared inside parentheses right after the query or mutation name.

What type of value does ID! represent in a variable declaration?

A A non-nullable ID

B A nullable ID

C An optional string

D A list of IDs

The exclamation mark means the ID is non-nullable and must be provided.

How do you pass variable values when sending a GraphQL query?

A As a separate JSON object alongside the query

B Inside the query string

C In the URL path

D In the query comments

Variable values are passed as a separate JSON object, not inside the query string.

Why are query variables useful in GraphQL?

A They speed up the server

B They make queries longer

C They allow comments inside queries

D They make queries reusable and secure

Variables help keep queries reusable and prevent injection attacks by separating data from query structure.

Explain how to use query variables in a GraphQL query from declaration to passing values.

Think about the three steps: declare, use, and pass values.

Why is it better to use query variables instead of hardcoding values in GraphQL queries?

Consider reusability and security benefits.