graphql-engine/docs/graphql/manual/schema/default-values/index.rst
2018-12-03 17:42:24 +05:30

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Setting default values for fields
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Let's say you want certain fields to have their values set automatically when not explicitly passed. You can do this in
the following ways:
- :doc:`Postgres defaults <postgres-defaults>`: configure default values, using fixed values or simple SQL functions,
for columns in the table definition. e.g. an auto-incrementing ``id``, a ``created_at`` timestamp, etc.
- :doc:`Custom SQL functions <sql-functions>`: set up Postgres triggers which run custom SQL functions/stored procedures
to set the values of certain columns on inserts/updates on the table. This is useful to set values of fields which
depend on other fields passed in the input. e.g. set ``submission_time`` of an online quiz as 1 hour from the
``start_time``.
- :doc:`Role based column presets <column-presets>`: set up presets, using session variables or fixed values, that are
applied when a new row is created with a particular :doc:`user role <../../auth/roles-variables>`. e.g. set a
``user_id`` field automatically from a session variable/Authorization header.
.. toctree::
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Postgres defaults <postgres-defaults>
Custom SQL functions/stored procedures <sql-functions>
Role based column presets <column-presets>