graphql-engine/server/lib/dc-api
David Overton 9921823915 GDC-189 custom aggregations
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## Description
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This PR allows DC agents to define custom aggregate functions for their scalar types.

### Related Issues
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GDC-189

### Solution and Design
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We added a new property `aggregate_functions` to the scalar types capabilities. This allows the agent author to specify a set of aggregate functions supported by each scalar type, along with the function's result type.

During GraphQL schema generation, the custom aggregate functions are available via a new method `getCustomAggregateOperators` on the `Backend` type class.
Custom functions are merged with the builtin aggregate functions when building GraphQL schemas for table aggregate fields and for `order_by` operators on array relations.

### Steps to test and verify
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• Codec tests for aggregate function capabilities have been added to the unit tests.
• Some custom aggregate operators have been added to the reference agent and are used in a new test in `api-tests`.

PR-URL: https://github.com/hasura/graphql-engine-mono/pull/6199
GitOrigin-RevId: e9c0d1617af93847c1493671fdbb794f573bde0c
2022-10-27 00:44:06 +00:00
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src GDC-189 custom aggregations 2022-10-27 00:44:06 +00:00
test GDC-189 custom aggregations 2022-10-27 00:44:06 +00:00
dc-api.cabal GDC-189 custom aggregations 2022-10-27 00:44:06 +00:00