GraphQL notes

GraphQl doest NOT replace SQL but it's a replacement for REST API.

Online tool here (opens new window)

protocol-agnostic

GraphQL itself is protocol-agnostic, meaning it doesn't dictate a specific network protocol for communication. It focuses on the data structure and query language for requesting and receiving data.

However, GraphQL is most commonly used with HTTP (Hypertext Transfer Protocol). Here's why:

• Widely Supported: HTTP is the foundation of the web, making it a familiar and universally supported choice for most servers and clients.
• Flexibility: HTTP offers various methods (GET, POST) that can be adapted to different GraphQL request types.
• Existing Tools and Libraries: A wealth of existing tools and libraries exist for handling HTTP communication, simplifying development with GraphQL.

Alternative Protocols:

While HTTP is dominant, GraphQL can theoretically be used with other protocols like:

• WebSockets: For real-time data updates where two-way communication is necessary.
• gRPC: For potential performance benefits, especially in high-performance environments with language compatibility for gRPC and Protocol Buffers.

Key Point: The network protocol choice primarily affects how data is transferred, while GraphQL handles the data structure and querying logic itself.

Queries

Basic

{
    allPeople {
        people {
            name
            birthYear
        }
    }
}

Limiting

{
    allPeople (first: 2) {
        people {
            name
            birthYear
        }
    }
}

Note: could use last instead of first

Combining with Fragment

query FirstAndLastTwoPeople {
    firstTwoPeople: allPeople (first: 2) {
        people {
           ...peopleFields
        }
    }
    lastTwoPeople: allPeople (first: 2) {
        people {
            ...peopleFields
        }
    }
}

fragment peopleFields on Person {
    name
    birthYear
    gender
}

Combining With Argument

query FirstAndLastNPeople($n: Int = 5) {
    firstNPeople: allPeople (first: $n) {
        people {
           ...peopleFields
        }
    }
    lastNPeople: allPeople (first: $n) {
        people {
            ...peopleFields
        }
    }
}

fragment peopleFields on Person {
    name
    birthYear
    gender
}

Combining With Directive

query FirstAndLastNPeople($n: Int = 5, $fetchFirst: Boolean = false) {
    firstNPeople: allPeople (first: $n) {
        people @include (if $fetchFirst) {
           ...peopleFields
        }
    }
    lastNPeople: allPeople (first: $n) {
        people {
            ...peopleFields
        }
    }
}

fragment peopleFields on Person {
    name
    birthYear
    gender
}

Note: could use @skip instead of @include

Mutations

mutation {
   updateUser( id: "1", data: {name: "Ban Admin"}) {
    id
    name
  }
}

References

• GraphQL Tutorial (opens new window)
• Online tool here (opens new window)