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8f4692d871
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/9174 GitOrigin-RevId: d440647ac04b9c1717ecf22a2dbfb8c5f22b7c7a
49 lines
2.1 KiB
Haskell
49 lines
2.1 KiB
Haskell
-- | Types and functions for interacting with and manipulating SQL enums represented by
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-- /single-column tables/, __not__ native Postgres enum types. Native enum types in Postgres are
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-- difficult to change, so we discourage their use, but we might add support for native enum types
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-- in the future.
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module Hasura.RQL.DDL.Schema.Enum
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( -- * Re-exports from "Hasura.RQL.Types.Column"
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EnumReference (..),
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EnumValues,
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EnumValueInfo (..),
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EnumValue (..),
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-- * Loading table info
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resolveEnumReferences,
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)
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where
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import Data.HashMap.Strict qualified as HashMap
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import Data.HashMap.Strict.NonEmpty qualified as NEHashMap
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import Data.Sequence qualified as Seq
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import Data.Sequence.NonEmpty qualified as NESeq
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import Hasura.Prelude
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import Hasura.RQL.Types.Backend
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import Hasura.RQL.Types.Column
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import Hasura.Table.Cache (ForeignKey (..), PrimaryKey (..), TableConfig (..))
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-- | Given a map of enum tables, computes all enum references implied by the given set of foreign
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-- keys. A foreign key constitutes an enum reference iff the following conditions hold:
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--
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-- 1. The key only includes a single column.
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-- 2. The referenced column is the table’s primary key.
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-- 3. The referenced table is, in fact, an enum table.
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resolveEnumReferences ::
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forall b.
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(Backend b) =>
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HashMap (TableName b) (PrimaryKey b (Column b), TableConfig b, EnumValues) ->
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HashSet (ForeignKey b) ->
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HashMap (Column b) (NonEmpty (EnumReference b))
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resolveEnumReferences enumTables =
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HashMap.fromListWith (<>) . map (fmap (:| [])) . mapMaybe resolveEnumReference . toList
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where
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resolveEnumReference :: ForeignKey b -> Maybe (Column b, EnumReference b)
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resolveEnumReference foreignKey = do
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[(localColumn, foreignColumn)] <- pure $ NEHashMap.toList (_fkColumnMapping @b foreignKey)
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let foreignKeyTableName = _fkForeignTable foreignKey
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(primaryKey, tConfig, enumValues) <- HashMap.lookup foreignKeyTableName enumTables
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let tableCustomName = _tcCustomName tConfig
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guard (_pkColumns primaryKey == foreignColumn NESeq.:<|| Seq.Empty)
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pure (localColumn, EnumReference foreignKeyTableName enumValues tableCustomName)
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