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97 lines
2.6 KiB
ReStructuredText
97 lines
2.6 KiB
ReStructuredText
Schema
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======
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A GraphQL **Schema** defines the types and relationship between **Fields** in your API.
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A Schema is created by supplying the root :ref:`ObjectType` of each operation, query (mandatory), mutation and subscription.
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Schema will collect all type definitions related to the root operations and then supplied to the validator and executor.
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.. code:: python
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my_schema = Schema(
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query=MyRootQuery,
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mutation=MyRootMutation,
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subscription=MyRootSubscription
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)
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A Root Query is just a special :ref:`ObjectType` that :ref:`defines the fields <Scalars>` that are the entrypoint for your API. Root Mutation and Root Subscription are similar to Root Query, but for different operation types:
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* Query fetches data
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* Mutation changes data and retrieves the changes
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* Subscription sends changes to clients in real time
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Review the `GraphQL documentation on Schema`_ for a brief overview of fields, schema and operations.
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.. _GraphQL documentation on Schema: https://graphql.org/learn/schema/
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Querying
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--------
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To query a schema, call the ``execute`` method on it. See :ref:`SchemaExecute` for more details.
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.. code:: python
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query_string = 'query whoIsMyBestFriend { myBestFriend { lastName } }'
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my_schema.execute(query_string)
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Types
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-----
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There are some cases where the schema cannot access all of the types that we plan to have.
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For example, when a field returns an ``Interface``, the schema doesn't know about any of the
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implementations.
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In this case, we need to use the ``types`` argument when creating the Schema.
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.. code:: python
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my_schema = Schema(
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query=MyRootQuery,
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types=[SomeExtraObjectType, ]
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)
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.. _SchemaAutoCamelCase:
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Auto camelCase field names
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--------------------------
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By default all field and argument names (that are not
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explicitly set with the ``name`` arg) will be converted from
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``snake_case`` to ``camelCase`` (as the API is usually being consumed by a js/mobile client)
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For example with the ObjectType
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.. code:: python
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class Person(graphene.ObjectType):
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last_name = graphene.String()
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other_name = graphene.String(name='_other_Name')
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the ``last_name`` field name is converted to ``lastName``.
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In case you don't want to apply this transformation, provide a ``name`` argument to the field constructor.
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``other_name`` converts to ``_other_Name`` (without further transformations).
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Your query should look like
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.. code::
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{
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lastName
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_other_Name
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}
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To disable this behavior, set the ``auto_camelcase`` to ``False`` upon schema instantiation.
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.. code:: python
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my_schema = Schema(
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query=MyRootQuery,
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auto_camelcase=False,
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)
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