What are Variables in Graphql?
In Graphql, Variables are used to parametrize queries and mutations. They allow developers to parameterize the queries and mutations to enable more dynamic content and reusable queries. Instead of adding hardcode values into the queries, variables provide a way to inject dynamic values at runtime.
Features of GraphQL Variables
- Dynamic Querying: GraphQL variables enable the creation of dynamic queries where values can be provided at runtime. This dynamic nature allows for a wide range of use cases, such as filtering, sorting, or specifying criteria based on user input.
- Multiple Variables in a Single Query: GraphQL queries can include multiple variables, each serving a specific purpose within the query. This capability allows for complex and parameterized queries without sacrificing readability.
- Variable Default Values: In GraphQL can have default values, providing a fallback in case a value is not explicitly provided during query execution. This feature enhances the flexibility of queries while maintaining a level of predictability.
Syntax of Variables in GrabhpQL
To use a variable in a GraphQL query, you must follow a specific syntax. Let’s break down the key components. Follow the following steps.
- Variables are declared within the parentheses of a query or mutation.
- In GrahphQL, each varaible starts with a dollar sign ($) followed by the variablle name and its type. There is the example of this variable.
query GetPerson($id: ID!) {
person(id: $id) {
name
age
address
}
}
In this query example, we can see ‘$id’ is a variable of type ID. This query fetches information about a person with specific id, actual value provided in the variable in the execution time.
Variables in GraphQL
GraphQL is a query language for API (Application Programming Interface). It was developed by Facebook in 2012 after they released it publicly in 2015. Graphql Provides a more efficient, powerful, and flexible alternative to traditional REST APIs. In this article, we will learn about variables in GraphQL.