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c1380e1daf
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/5069 GitOrigin-RevId: acd80975c162935d5594e55db47228cf689e5fd7
90 lines
3.4 KiB
Haskell
90 lines
3.4 KiB
Haskell
module Hasura.Backends.DataConnector.IR.Query
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( QueryRequest (..),
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Query (..),
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Field (..),
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RelationshipField (..),
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)
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where
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import Data.Aeson (ToJSON)
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import Data.Aeson qualified as J
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import Hasura.Backends.DataConnector.IR.Aggregate qualified as IR.A
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import Hasura.Backends.DataConnector.IR.Column qualified as IR.C
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import Hasura.Backends.DataConnector.IR.Expression qualified as IR.E
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import Hasura.Backends.DataConnector.IR.OrderBy qualified as IR.O
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import Hasura.Backends.DataConnector.IR.Relationships qualified as IR.R
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import Hasura.Backends.DataConnector.IR.Table qualified as IR.T
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import Hasura.Prelude
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-- | An abstract request to retrieve structured data from some source.
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data QueryRequest = QueryRequest
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{ _qrTable :: IR.T.Name,
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_qrTableRelationships :: IR.R.TableRelationships,
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_qrQuery :: Query
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}
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deriving stock (Data, Eq, Generic, Ord, Show)
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-- NOTE: The 'ToJSON' instance is only intended for logging purposes.
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instance ToJSON QueryRequest where
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toJSON = J.genericToJSON J.defaultOptions
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-- | The details of a query against a table
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data Query = Query
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{ -- Map of field name to Field definition.
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_qFields :: HashMap Text Field,
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-- Map of aggregate field name to Aggregate definition
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_qAggregates :: HashMap Text IR.A.Aggregate,
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-- | Optionally limit to N results.
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_qLimit :: Maybe Int,
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-- | Optionally offset from the Nth result.
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_qOffset :: Maybe Int,
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-- | Optionally constrain the results to satisfy some predicate.
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_qWhere :: Maybe IR.E.Expression,
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-- | Optionally order the results by the value of one or more fields.
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_qOrderBy :: [IR.O.OrderBy]
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}
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deriving stock (Data, Eq, Generic, Ord, Show)
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-- NOTE: The 'ToJSON' instance is only intended for logging purposes.
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instance ToJSON Query where
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toJSON = J.genericToJSON J.defaultOptions
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-- | The specific fields that are targeted by a 'Query'.
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--
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-- A field conceptually falls under one of the two following categories:
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-- 1. a "column" within the data store that the query is being issued against
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-- 2. a "relationship", which indicates that the field is the result of
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-- another query that must be executed on its own
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-- 3. a "literal", which represents a piece of text, such as a
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-- '__typename' field, which will appear in the final output and is
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-- provided by HGE and not the Agent.
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-- NOTE: The 'ToJSON' instance is only intended for logging purposes.
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data Field
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= ColumnField IR.C.Name
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| RelField RelationshipField
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| LiteralField Text
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deriving stock (Data, Eq, Generic, Ord, Show)
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instance ToJSON Field where
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toJSON = J.genericToJSON J.defaultOptions
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-- | A relationship consists of the following components:
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-- - a sub-query, from the perspective that a relationship field will occur
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-- within a broader 'Query'
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-- - a join condition relating the data returned by the sub-query with that
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-- of the broader 'Query'
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--
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-- cf. https://en.wikipedia.org/wiki/Join_(SQL)
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-- https://www.postgresql.org/docs/13/tutorial-join.html
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-- https://www.postgresql.org/docs/13/queries-table-expressions.html#QUERIES-FROM
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--
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-- NOTE: The 'ToJSON' instance is only intended for logging purposes.
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data RelationshipField = RelationshipField
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{ _rfRelationship :: IR.R.RelationshipName,
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_rfQuery :: Query
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}
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deriving stock (Eq, Ord, Show, Generic, Data)
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instance ToJSON RelationshipField where
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toJSON = J.genericToJSON J.defaultOptions
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