mirror of
https://github.com/hasura/graphql-engine.git
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84027dad04
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/2889 GitOrigin-RevId: 49c5d59a6f817832f11b1773b078aa24cc650ab5
601 lines
24 KiB
Haskell
601 lines
24 KiB
Haskell
{-# OPTIONS_GHC -fno-warn-orphans #-}
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module Hasura.Backends.MSSQL.Instances.Execute
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( MultiplexedQuery' (..),
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multiplexRootReselect,
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)
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where
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import Control.Monad.Trans.Control (MonadBaseControl)
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import Control.Monad.Validate qualified as V
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import Data.Aeson.Extended qualified as J
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import Data.HashMap.Strict qualified as Map
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import Data.HashMap.Strict.InsOrd qualified as OMap
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import Data.HashSet qualified as Set
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import Data.List.NonEmpty qualified as NE
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import Data.Text.Extended qualified as T
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import Database.MSSQL.Transaction qualified as Tx
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import Database.ODBC.Internal qualified as ODBCI
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import Database.ODBC.SQLServer qualified as ODBC
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import Hasura.Backends.MSSQL.Connection
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import Hasura.Backends.MSSQL.FromIr as TSQL
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import Hasura.Backends.MSSQL.Plan
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import Hasura.Backends.MSSQL.SQL.Value (txtEncodedColVal)
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import Hasura.Backends.MSSQL.ToQuery as TQ
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import Hasura.Backends.MSSQL.Types as TSQL
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import Hasura.Base.Error
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import Hasura.EncJSON
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import Hasura.GraphQL.Execute.Backend
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import Hasura.GraphQL.Execute.LiveQuery.Plan
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import Hasura.GraphQL.Namespace (RootFieldAlias (..), RootFieldMap)
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import Hasura.GraphQL.Parser
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import Hasura.Prelude
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import Hasura.RQL.IR
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import Hasura.RQL.IR qualified as IR
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import Hasura.RQL.Types
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import Hasura.RQL.Types qualified as RQLTypes
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import Hasura.RQL.Types.Column qualified as RQLColumn
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import Hasura.SQL.AnyBackend qualified as AB
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import Hasura.Session
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import Language.GraphQL.Draft.Syntax qualified as G
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instance BackendExecute 'MSSQL where
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type PreparedQuery 'MSSQL = Text
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type MultiplexedQuery 'MSSQL = MultiplexedQuery'
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type ExecutionMonad 'MSSQL = ExceptT QErr IO
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mkDBQueryPlan = msDBQueryPlan
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mkDBMutationPlan = msDBMutationPlan
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mkDBSubscriptionPlan = msDBSubscriptionPlan
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mkDBQueryExplain = msDBQueryExplain
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mkLiveQueryExplain = msDBLiveQueryExplain
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-- NOTE: Currently unimplemented!.
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--
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-- This function is just a stub for future implementation; for now it just
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-- throws a 500 error.
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mkDBRemoteRelationshipPlan =
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msDBRemoteRelationshipPlan
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-- Multiplexed query
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newtype MultiplexedQuery' = MultiplexedQuery' Reselect
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instance T.ToTxt MultiplexedQuery' where
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toTxt (MultiplexedQuery' reselect) = T.toTxt $ toQueryPretty $ fromReselect reselect
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-- Query
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msDBQueryPlan ::
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forall m.
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( MonadError QErr m
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) =>
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UserInfo ->
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SourceName ->
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SourceConfig 'MSSQL ->
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QueryDB 'MSSQL (Const Void) (UnpreparedValue 'MSSQL) ->
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m (DBStepInfo 'MSSQL)
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msDBQueryPlan userInfo sourceName sourceConfig qrf = do
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-- TODO (naveen): Append Query Tags to the query
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let sessionVariables = _uiSession userInfo
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statement <- planQuery sessionVariables qrf
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let printer = fromSelect statement
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queryString = ODBC.renderQuery $ toQueryPretty printer
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pool = _mscConnectionPool sourceConfig
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odbcQuery = encJFromText <$> runJSONPathQuery pool (toQueryFlat printer)
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pure $ DBStepInfo @'MSSQL sourceName sourceConfig (Just queryString) odbcQuery
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runShowplan ::
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ODBC.Query -> ODBC.Connection -> IO [Text]
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runShowplan query conn = do
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ODBC.exec conn "SET SHOWPLAN_TEXT ON"
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texts <- ODBC.query conn query
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ODBC.exec conn "SET SHOWPLAN_TEXT OFF"
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-- we don't need to use 'finally' here - if an exception occurs,
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-- the connection is removed from the resource pool in 'withResource'.
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pure texts
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msDBQueryExplain ::
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MonadError QErr m =>
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RootFieldAlias ->
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UserInfo ->
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SourceName ->
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SourceConfig 'MSSQL ->
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QueryDB 'MSSQL (Const Void) (UnpreparedValue 'MSSQL) ->
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m (AB.AnyBackend DBStepInfo)
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msDBQueryExplain fieldName userInfo sourceName sourceConfig qrf = do
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let sessionVariables = _uiSession userInfo
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statement <- planQuery sessionVariables qrf
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let query = toQueryPretty (fromSelect statement)
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queryString = ODBC.renderQuery query
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pool = _mscConnectionPool sourceConfig
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odbcQuery =
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withMSSQLPool
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pool
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( \conn -> liftIO do
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showplan <- runShowplan query conn
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pure
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( encJFromJValue $
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ExplainPlan
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fieldName
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(Just queryString)
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(Just showplan)
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)
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)
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pure $
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AB.mkAnyBackend $
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DBStepInfo @'MSSQL sourceName sourceConfig Nothing odbcQuery
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msDBLiveQueryExplain ::
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(MonadIO m, MonadBaseControl IO m, MonadError QErr m) =>
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LiveQueryPlan 'MSSQL (MultiplexedQuery 'MSSQL) ->
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m LiveQueryPlanExplanation
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msDBLiveQueryExplain (LiveQueryPlan plan sourceConfig variables _) = do
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let (MultiplexedQuery' reselect) = _plqpQuery plan
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query = toQueryPretty $ fromSelect $ multiplexRootReselect [(dummyCohortId, variables)] reselect
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pool = _mscConnectionPool sourceConfig
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explainInfo <- withMSSQLPool pool (liftIO . runShowplan query)
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pure $ LiveQueryPlanExplanation (T.toTxt query) explainInfo variables
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--------------------------------------------------------------------------------
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-- Producing the correct SQL-level list comprehension to multiplex a query
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-- Problem description:
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--
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-- Generate a query that repeats the same query N times but with
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-- certain slots replaced:
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--
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-- [ Select x y | (x,y) <- [..] ]
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--
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multiplexRootReselect ::
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[(CohortId, CohortVariables)] ->
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TSQL.Reselect ->
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TSQL.Select
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multiplexRootReselect variables rootReselect =
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emptySelect
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{ selectTop = NoTop,
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selectProjections =
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[ FieldNameProjection
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Aliased
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{ aliasedThing =
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TSQL.FieldName
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{ fieldNameEntity = rowAlias,
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fieldName = resultIdAlias
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},
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aliasedAlias = resultIdAlias
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},
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ExpressionProjection
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Aliased
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{ aliasedThing =
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ColumnExpression
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( TSQL.FieldName
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{ fieldNameEntity = resultAlias,
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fieldName = TSQL.jsonFieldName
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}
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),
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aliasedAlias = resultAlias
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}
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],
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selectFrom =
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Just $
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FromOpenJson
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Aliased
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{ aliasedThing =
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OpenJson
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{ openJsonExpression =
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ValueExpression (ODBC.TextValue $ lbsToTxt $ J.encode variables),
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openJsonWith =
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Just $
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NE.fromList
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[ UuidField resultIdAlias (Just $ IndexPath RootPath 0),
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JsonField resultVarsAlias (Just $ IndexPath RootPath 1)
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]
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},
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aliasedAlias = rowAlias
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},
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selectJoins =
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[ Join
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{ joinSource = JoinReselect rootReselect,
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joinJoinAlias =
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JoinAlias
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{ joinAliasEntity = resultAlias,
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joinAliasField = Just TSQL.jsonFieldName
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}
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}
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],
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selectWhere = Where mempty,
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selectFor =
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JsonFor ForJson {jsonCardinality = JsonArray, jsonRoot = NoRoot},
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selectOrderBy = Nothing,
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selectOffset = Nothing
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}
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-- mutation
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msDBMutationPlan ::
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forall m.
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( MonadError QErr m
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) =>
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UserInfo ->
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Bool ->
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SourceName ->
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SourceConfig 'MSSQL ->
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MutationDB 'MSSQL (Const Void) (UnpreparedValue 'MSSQL) ->
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m (DBStepInfo 'MSSQL)
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msDBMutationPlan userInfo stringifyNum sourceName sourceConfig mrf = do
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go <$> case mrf of
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MDBInsert annInsert -> executeInsert userInfo stringifyNum sourceConfig annInsert
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MDBDelete _annDelete -> throw400 NotSupported "delete mutations are not supported in MSSQL"
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MDBFunction {} -> throw400 NotSupported "function mutations are not supported in MSSQL"
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where
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go v = DBStepInfo @'MSSQL sourceName sourceConfig Nothing v
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-- | Execution of a MSSQL insert mutation broadly involves two steps.
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--
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-- -- insert_table(objects: [
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-- -- {column1: value1, column2: value2},
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-- -- {column1: value3, column2: value4}
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-- -- ]
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-- -- ){
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-- -- affected_rows
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-- -- returning {
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-- -- column1
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-- -- column2
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-- -- }
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-- -- }
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-- --
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-- Step 1: Inserting rows into the table
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-- --
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-- -- a. Generate an SQL Insert statement from the GraphQL insert mutation with OUTPUT expression to return
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-- -- primary key column values after insertion.
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-- -- b. Before insert, Set IDENTITY_INSERT to ON if any insert row contains atleast one identity column.
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-- --
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-- -- SET IDENTITY_INSERT some_table ON;
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-- -- INSERT INTO some_table (column1, column2) OUTPUT INSERTED.pkey_column1, INSERTED.pkey_column2 VALUES (value1, value2), (value3, value4);
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-- --
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-- Step 2: Generation of the mutation response
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-- --
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-- -- An SQL statement is generated and when executed it returns the mutation selection set containing 'affected_rows' and 'returning' field values.
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-- -- The statement is generated with multiple sub select queries explained below:
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-- --
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-- -- a. A SQL Select statement to fetch only inserted rows from the table using primary key column values fetched from
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-- -- Step 1 in the WHERE clause
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-- --
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-- -- <table_select> :=
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-- -- SELECT * FROM some_table WHERE (pkey_column1 = value1 AND pkey_column2 = value2) OR (pkey_column1 = value3 AND pkey_column2 = value4)
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-- --
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-- -- The above select statement is referred through a common table expression - "WITH [with_alias] AS (<table_select>)"
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-- --
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-- -- b. The 'affected_rows' field value is obtained by using COUNT aggregation and the 'returning' field selection set is translated to
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-- -- a SQL select statement using @'mkSQLSelect'.
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-- --
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-- -- <mutation_output_select> :=
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-- -- SELECT (SELECT COUNT(*) FROM [with_alias]) AS [affected_rows], (select_from_returning) AS [returning] FOR JSON PATH, INCLUDE_NULL_VALUES, WITHOUT_ARRAY_WRAPPER
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-- --
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-- -- c. Evaluate the check constraint using CASE expression. We use SUM aggregation to check if any inserted row has failed the check constraint.
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-- --
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-- -- <check_constraint_select> :=
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-- -- SELECT SUM(CASE WHEN <check_boolean_expression> THEN 0 ELSE 1 END) FROM [with_alias]
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-- --
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-- -- d. The final select statement look like
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-- --
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-- -- WITH "with_alias" AS (<table_select>)
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-- -- SELECT (<mutation_output_select>) AS [mutation_response], (<check_constraint_select>) AS [check_constraint_select]
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-- --
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-- -- When executed, the above statement returns a single row with mutation response as a string value and check constraint result as an integer value.
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executeInsert ::
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MonadError QErr m =>
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UserInfo ->
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Bool ->
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SourceConfig 'MSSQL ->
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AnnInsert 'MSSQL (Const Void) (UnpreparedValue 'MSSQL) ->
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m (ExceptT QErr IO EncJSON)
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executeInsert userInfo stringifyNum sourceConfig annInsert = do
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-- Convert the leaf values from @'UnpreparedValue' to sql @'Expression'
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insert <- traverse (prepareValueQuery sessionVariables) annInsert
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let insertTx = buildInsertTx insert
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pure $ withMSSQLPool pool $ Tx.runTxE fromMSSQLTxError insertTx
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where
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sessionVariables = _uiSession userInfo
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pool = _mscConnectionPool sourceConfig
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table = _aiTableName $ _aiData annInsert
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withSelectTableAlias = "t_" <> tableName table
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withAlias = "with_alias"
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buildInsertTx :: AnnInsert 'MSSQL (Const Void) Expression -> Tx.TxET QErr IO EncJSON
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buildInsertTx insert = do
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let identityColumns = _mssqlIdentityColumns $ _aiExtraInsertData $ _aiData insert
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insertColumns = concatMap (map fst . getInsertColumns) $ _aiInsObj $ _aiData insert
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-- Set identity insert to ON if insert object contains identity columns
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when (any (`elem` identityColumns) insertColumns) $
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Tx.unitQueryE fromMSSQLTxError $
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toQueryFlat $
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TQ.fromSetIdentityInsert $
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SetIdenityInsert (_aiTableName $ _aiData insert) SetON
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-- Generate the INSERT query
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let insertQuery = toQueryFlat $ TQ.fromInsert $ TSQL.fromInsert insert
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fromODBCException e =
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(err400 MSSQLError "insert query exception") {qeInternal = Just (ExtraInternal $ odbcExceptionToJSONValue e)}
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-- Execute the INSERT query and fetch the primary key values
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primaryKeyValues <- Tx.buildGenericTxE fromODBCException $ \conn -> ODBCI.query conn (ODBC.renderQuery insertQuery)
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let withSelect = generateWithSelect primaryKeyValues
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-- WITH [with_alias] AS (select_query)
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withExpression = With $ pure $ Aliased withSelect withAlias
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mutationOutputSelect <- mkMutationOutputSelect stringifyNum withAlias $ _aiOutput insert
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let (checkCondition, _) = _aiCheckCond $ _aiData insert
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-- The check constraint is translated to boolean expression
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checkBoolExp <-
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V.runValidate (runFromIr $ runReaderT (fromGBoolExp checkCondition) (EntityAlias withAlias))
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`onLeft` (throw500 . tshow)
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-- SELECT (<mutation_output_select>) AS [mutation_response], (<check_constraint_select>) AS [check_constraint_select]
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let mutationOutputCheckConstraintSelect = selectMutationOutputAndCheckCondition mutationOutputSelect checkBoolExp
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-- WITH "with_alias" AS (<table_select>)
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-- SELECT (<mutation_output_select>) AS [mutation_response], (<check_constraint_select>) AS [check_constraint_select]
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finalSelect = mutationOutputCheckConstraintSelect {selectWith = Just withExpression}
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(responseText, checkConditionInt) <- Tx.singleRowQueryE fromMSSQLTxError (toQueryFlat $ TQ.fromSelect finalSelect)
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unless (checkConditionInt == (0 :: Int)) $
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throw400 PermissionError "check constraint of an insert permission has failed"
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pure $ encJFromText responseText
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columnFieldExpression :: ODBCI.Column -> Expression
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columnFieldExpression column =
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ColumnExpression $ TSQL.FieldName (ODBCI.columnName column) withSelectTableAlias
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generateWithSelect :: [[(ODBCI.Column, ODBC.Value)]] -> Select
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generateWithSelect pkeyValues =
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emptySelect
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{ selectProjections = [StarProjection],
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selectFrom = Just $ FromQualifiedTable $ Aliased table withSelectTableAlias,
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selectWhere = whereExpression
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}
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where
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-- WHERE (column1 = value1 AND column2 = value2) OR (column1 = value3 AND column2 = value4)
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whereExpression =
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let mkColumnEqExpression (column, value) =
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OpExpression EQ' (columnFieldExpression column) (ValueExpression value)
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in Where $ pure $ OrExpression $ map (AndExpression . map mkColumnEqExpression) pkeyValues
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generateCheckConstraintSelect :: Expression -> Select
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generateCheckConstraintSelect checkBoolExp =
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let zeroValue = ValueExpression $ ODBC.IntValue 0
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oneValue = ValueExpression $ ODBC.IntValue 1
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caseExpression = ConditionalExpression checkBoolExp zeroValue oneValue
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sumAggregate = OpAggregate "SUM" [caseExpression]
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in emptySelect
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{ selectProjections = [AggregateProjection (Aliased sumAggregate "check")],
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selectFrom = Just $ TSQL.FromIdentifier withAlias
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}
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selectMutationOutputAndCheckCondition :: Select -> Expression -> Select
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selectMutationOutputAndCheckCondition mutationOutputSelect checkBoolExp =
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let mutationOutputProjection =
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ExpressionProjection $ Aliased (SelectExpression mutationOutputSelect) "mutation_response"
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checkConstraintProjection =
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ExpressionProjection $ Aliased (SelectExpression (generateCheckConstraintSelect checkBoolExp)) "check_constraint_select"
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in emptySelect {selectProjections = [mutationOutputProjection, checkConstraintProjection]}
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-- | Generate a SQL SELECT statement which outputs the mutation response
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--
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-- For multi row inserts:
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-- SELECT (SELECT COUNT(*) FROM [with_alias]) AS [affected_rows], (select_from_returning) AS [returning] FOR JSON PATH, INCLUDE_NULL_VALUES, WITHOUT_ARRAY_WRAPPER
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--
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-- For single row insert: the selection set is translated to SQL query using @'mkSQLSelect'
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mkMutationOutputSelect ::
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(MonadError QErr m) =>
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Bool ->
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Text ->
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MutationOutputG 'MSSQL (Const Void) Expression ->
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m Select
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mkMutationOutputSelect stringifyNum withAlias = \case
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IR.MOutMultirowFields multiRowFields -> do
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projections <- forM multiRowFields $ \(fieldName, field') -> do
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let mkProjection = ExpressionProjection . flip Aliased (getFieldNameTxt fieldName) . SelectExpression
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mkProjection <$> case field' of
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IR.MCount -> pure countSelect
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IR.MExp t -> pure $ textSelect t
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IR.MRet returningFields -> mkSelect JASMultipleRows returningFields
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let forJson = JsonFor $ ForJson JsonSingleton NoRoot
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pure emptySelect {selectFor = forJson, selectProjections = projections}
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IR.MOutSinglerowObject singleRowField -> mkSelect JASSingleObject singleRowField
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where
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mkSelect jsonAggSelect annFields = do
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let annSelect = IR.AnnSelectG annFields (IR.FromIdentifier withAlias) IR.noTablePermissions IR.noSelectArgs stringifyNum
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V.runValidate (runFromIr $ mkSQLSelect jsonAggSelect annSelect) `onLeft` (throw500 . tshow)
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-- SELECT COUNT(*) FROM [with_alias]
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countSelect =
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let countProjection = AggregateProjection $ Aliased (CountAggregate StarCountable) "count"
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in emptySelect
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{ selectProjections = [countProjection],
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selectFrom = Just $ TSQL.FromIdentifier withAlias
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}
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textSelect t =
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let textProjection = ExpressionProjection $ Aliased (ValueExpression (ODBC.TextValue t)) "exp"
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in emptySelect {selectProjections = [textProjection]}
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-- subscription
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msDBSubscriptionPlan ::
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forall m.
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( MonadError QErr m,
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MonadIO m,
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MonadBaseControl IO m
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) =>
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UserInfo ->
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SourceName ->
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SourceConfig 'MSSQL ->
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Maybe G.Name ->
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RootFieldMap (QueryDB 'MSSQL (Const Void) (UnpreparedValue 'MSSQL)) ->
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m (LiveQueryPlan 'MSSQL (MultiplexedQuery 'MSSQL))
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msDBSubscriptionPlan UserInfo {_uiSession, _uiRole} _sourceName sourceConfig namespace rootFields = do
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(reselect, prepareState) <- planSubscription (OMap.mapKeys _rfaAlias rootFields) _uiSession
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cohortVariables <- prepareStateCohortVariables sourceConfig _uiSession prepareState
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let parameterizedPlan = ParameterizedLiveQueryPlan _uiRole $ MultiplexedQuery' reselect
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pure $
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LiveQueryPlan parameterizedPlan sourceConfig cohortVariables namespace
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prepareStateCohortVariables :: (MonadError QErr m, MonadIO m, MonadBaseControl IO m) => SourceConfig 'MSSQL -> SessionVariables -> PrepareState -> m CohortVariables
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prepareStateCohortVariables sourceConfig session prepState = do
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(namedVars, posVars) <- validateVariables sourceConfig session prepState
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let PrepareState {sessionVariables} = prepState
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pure $
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mkCohortVariables
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sessionVariables
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session
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namedVars
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posVars
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-- | Ensure that the set of variables (with value instantiations) that occur in
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-- a (RQL) query produce a well-formed and executable (SQL) query when
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-- considered in isolation.
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--
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-- This helps avoiding cascading failures in multiplexed queries.
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--
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-- c.f. https://github.com/hasura/graphql-engine-mono/issues/1210.
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validateVariables ::
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(MonadError QErr m, MonadIO m, MonadBaseControl IO m) =>
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SourceConfig 'MSSQL ->
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SessionVariables ->
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PrepareState ->
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m (ValidatedQueryVariables, ValidatedSyntheticVariables)
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validateVariables sourceConfig sessionVariableValues prepState = do
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let PrepareState {sessionVariables, namedArguments, positionalArguments} = prepState
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-- We generate a single 'canary' query in the form:
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--
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-- SELECT ... [session].[x-hasura-foo] as [x-hasura-foo], ... as a, ... as b, ...
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-- FROM OPENJSON('...')
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-- WITH ([x-hasura-foo] NVARCHAR(MAX)) as [session]
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--
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-- where 'a', 'b', etc. are aliases given to positional arguments.
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-- Named arguments and session variables are aliased to themselves.
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--
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-- The idea being that if the canary query succeeds we can be
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-- reasonably confident that adding these variables to a query being
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-- polled will not crash the poller.
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occSessionVars =
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filterSessionVariables
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(\k _ -> Set.member k sessionVariables)
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sessionVariableValues
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expSes, expNamed, expPos :: [Aliased Expression]
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expSes = sessionReference <$> getSessionVariables occSessionVars
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expNamed =
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map
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( \(n, v) -> Aliased (ValueExpression (RQLColumn.cvValue v)) (G.unName n)
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)
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$ Map.toList $ namedArguments
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-- For positional args we need to be a bit careful not to capture names
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-- from expNamed and expSes (however unlikely)
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expPos =
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zipWith
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(\n v -> Aliased (ValueExpression (RQLColumn.cvValue v)) n)
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(freshVars (expNamed <> expSes))
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positionalArguments
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projAll :: [Projection]
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projAll = map ExpressionProjection (expSes <> expNamed <> expPos)
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canaryQuery =
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if null projAll
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then Nothing
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else
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Just $
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renderQuery
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emptySelect
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{ selectProjections = projAll,
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selectFrom = sessionOpenJson occSessionVars
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}
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onJust
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canaryQuery
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( \q -> do
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_ :: [[ODBC.Value]] <- withMSSQLPool (_mscConnectionPool sourceConfig) (`ODBC.query` q)
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pure ()
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)
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pure
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( ValidatedVariables $ txtEncodedColVal <$> namedArguments,
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ValidatedVariables $ txtEncodedColVal <$> positionalArguments
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)
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where
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renderQuery :: Select -> ODBC.Query
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renderQuery = toQueryFlat . fromSelect
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freshVars :: [Aliased a] -> [Text]
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freshVars boundNames = filter (not . (`elem` map aliasedAlias boundNames)) chars
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-- Infinite list of expression aliases.
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chars :: [Text]
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chars = [y T.<>> x | y <- [""] <|> chars, x <- ['a' .. 'z']]
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sessionOpenJson :: SessionVariables -> Maybe From
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sessionOpenJson occSessionVars =
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nonEmpty (getSessionVariables occSessionVars)
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<&> \fields ->
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FromOpenJson $
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Aliased
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( OpenJson
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(ValueExpression $ ODBC.TextValue $ lbsToTxt $ J.encode occSessionVars)
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(pure (sessField <$> fields))
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)
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"session"
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sessField :: Text -> JsonFieldSpec
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sessField var = StringField var Nothing
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sessionReference :: Text -> Aliased Expression
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sessionReference var = Aliased (ColumnExpression (TSQL.FieldName var "session")) var
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--------------------------------------------------------------------------------
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-- Remote Relationships (e.g. DB-to-DB Joins, remote schema joins, etc.)
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--------------------------------------------------------------------------------
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-- | Construct an action (i.e. 'DBStepInfo') which can marshal some remote
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-- relationship information into a form that SQL Server can query against.
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--
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-- XXX: Currently unimplemented; the Postgres implementation uses
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-- @jsonb_to_recordset@ to query the remote relationship, however this
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-- functionality doesn't exist in SQL Server.
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--
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-- NOTE: The following typeclass constraints will be necessary when implementing
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-- this function for real:
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--
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-- @
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-- MonadQueryTags m
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-- Backend 'MSSQL
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-- @
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msDBRemoteRelationshipPlan ::
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|
forall m.
|
|
( MonadError QErr m
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|
) =>
|
|
UserInfo ->
|
|
SourceName ->
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SourceConfig 'MSSQL ->
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|
-- | List of json objects, each of which becomes a row of the table.
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NonEmpty J.Object ->
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|
-- | The above objects have this schema
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--
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-- XXX: What is this for/what does this mean?
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HashMap RQLTypes.FieldName (RQLTypes.Column 'MSSQL, RQLTypes.ScalarType 'MSSQL) ->
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|
-- | This is a field name from the lhs that *has* to be selected in the
|
|
-- response along with the relationship.
|
|
RQLTypes.FieldName ->
|
|
(RQLTypes.FieldName, SourceRelationshipSelection 'MSSQL (Const Void) UnpreparedValue) ->
|
|
m (DBStepInfo 'MSSQL)
|
|
msDBRemoteRelationshipPlan _userInfo _sourceName _sourceConfig _lhs _lhsSchema _argumentId _relationship = do
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|
throw500 "mkDBRemoteRelationshipPlan: SQL Server (MSSQL) does not currently support generalized joins."
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