Graphql queries: Difference between revisions
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= Basics = | = Basics = | ||
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Graphql objects are arranged in a [https://en.wikipedia.org/wiki/Directed_acyclic_graph DAG].<br> | |||
Top-level nodes can be queried directly,<br> | |||
other objects are accessed through fields on top-level items, | |||
optionally passing through an arbitrary number of child node-fields. | |||
<syntaxhighlight lang="graphql"> | |||
</syntaxhighlight> | |||
<syntaxhighlight lang="graphql"> | |||
# select id/name fields on Project | |||
{ | |||
Project { # <-- a top-level node | |||
id # <-- fields on that node | |||
name | |||
} | |||
} | |||
</syntaxhighlight> | |||
</blockquote><!-- Basics --> | </blockquote><!-- Basics --> | ||
Revision as of 03:31, 2 September 2021
Basics
Graphql objects are arranged in a DAG.
Top-level nodes can be queried directly,
other objects are accessed through fields on top-level items, optionally passing through an arbitrary number of child node-fields.# select id/name fields on Project { Project { # <-- a top-level node id # <-- fields on that node name } }
Without Params
Some fields may be implied by the REST API path, so no params are required.
# https://tracking-system/projects/1/graphql { name createdAt }
With Params
Other times, you may need to use parameters in your query.
# https://tracking-system/projects/1/graphql { tasks($name: String){ status createdAt } }{"name": "clean bathroom"}
Fragments
Fragments are a named group of fields to select on a specific object-type.
Fragments let you:
- Select type-specific fields in heterogenous collections
- Concisely describe a group of fields, DRY out queries
- Concisely describe Recursive/Nested nodes
TODO:
Example schema
named fragments
{ children { ...nodeFields children { ...nodeFields { children { ...nodeFields } } } } } fragment nodeFields on Node { id text colour background-colour }inline fragments
{ rentalInventory { vehicles { wheels # select on both Car and Motorcycle passengers ... on Car { # select on Car items only numSeatbelts numAirbags } ... on Motorcycle { # select on Motorcycle items only numSaddleBags } } } }