Graphql relationships: Difference between revisions
From wikinotes
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= Edges/Connections = | = Edges/Connections = | ||
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Connections and Edges '''are not''' a part of graphql syntax,<br> | |||
they are a schema design-pattern that is '''sometimes implemented in API libraries'''. | |||
{{ TODO | | {{ TODO | | ||
This is unconfirmed and unclear. redo }} | This is unconfirmed and unclear. redo }} |
Revision as of 18:56, 4 September 2021
Interfaces
In graphql, an interface is a group of fields that multiple objects may use.
A type that implements that interface must define all fields required by the interface.
Note you can implement multiple interfaces.# schema interface Animal { species: String! age: Int! } type Duck implements Animal { species: String! age: Int! quack: String! }You can return an
Animal
(which really returns any of the subtypes).
When referring to fields not part of the return type, you need to specify the object it belongs to.{ animal { species age ... on Duck { quack } } }
Edges/Connections
Connections and Edges are not a part of graphql syntax,
they are a schema design-pattern that is sometimes implemented in API libraries.TODO:
This is unconfirmed and unclear. redo
See https://graphql.org/learn/pagination/#end-of-list-counts-and-connections
# NOTE: UNTESTED type Class { subject: String students( # a connection -- define supplemental query-params age: Int ) StudentConnection! } type StudentConnection { edges: [StudentEdge] nodes: [Student] } type StudentEdge { node: Student } type Student { firstname: String! lastname: String! age: Int! }# untested, probably wrong query MathClassStudents { Class(subject: "Math") { students(first: 2, age: 25) { edges { Student } } } }