Update placeholder propergation method.

relational-join/src/Database/Relational/Query/Derives.hs

@@ -15,7 +15,7 @@ import qualified Database.Relational.Query.Table as Table
 import Database.Relational.Query.Projectable (placeholder, (.=.))
 import Database.Relational.Query.ProjectableExtended ((!))
 import Database.Relational.Query.Monad.Class (wheres)
-import Database.Relational.Query.Relation (Relation, relation, query)
+import Database.Relational.Query.Relation (Relation, relation', query)
 import Database.Relational.Query.Constraint
    (Key, Primary, Unique, projectionKey, uniqueKey,
     HasConstraintKey(constraintKey))
@@ -26,10 +26,11 @@ unique :: PersistableWidth p
        => Key Unique a p
        -> Relation () a
        -> Relation p a
-unique uk rel = relation $ do
+unique uk rel = relation' $ do
   q <- query rel
-  wheres $ q ! projectionKey uk .=. placeholder
-  return q
+  let (param, ph) = placeholder
+  wheres $ q ! projectionKey uk .=. ph
+  return (param, q)
 
 primary' :: PersistableWidth p
          => Key Primary a p

relational-join/src/Database/Relational/Query/Projectable.hs

@@ -89,9 +89,6 @@ instance SqlProjectable Aggregation where
 valueNull :: SqlProjectable p => p (Maybe a)
 valueNull =  unsafeProjectSql "NULL"
 
-placeholder :: SqlProjectable p => p t
-placeholder =  unsafeProjectSql "?"
-
 value :: (ShowConstantSQL t, SqlProjectable p) => t -> p t
 value =  unsafeProjectSql . showConstantSQL
 
@@ -220,6 +217,9 @@ addPlaceHolders =  fmap ((,) PlaceHolders)
 unsafeCastPlaceHolders :: PlaceHolders a -> PlaceHolders b
 unsafeCastPlaceHolders PlaceHolders = PlaceHolders
 
+placeholder :: SqlProjectable p => (PlaceHolders t, p t)
+placeholder =  (PlaceHolders, unsafeProjectSql "?")
+
 
 class ProjectableZip p where
   projectZip :: p a -> p b -> p (a, b)

relational-join/src/Database/Relational/Query/Relation.hs

@@ -14,8 +14,6 @@ module Database.Relational.Query.Relation (
 
   sqlFromRelation,
 
-  -- subQueryFromRelation,
-
   nested, width
   ) where
 
@@ -85,13 +83,13 @@ queryMaybe' pr =  do
 queryMaybe :: MonadQuery m => Relation () r -> m (Projection (Maybe r))
 queryMaybe =  fmap snd . queryMaybe'
 
-relation :: QuerySimple (Projection r) -> Relation p r
+relation :: QuerySimple (Projection r) -> Relation () r
 relation =  SimpleRel
 
 relation' :: QuerySimple (PlaceHolders p, Projection r) -> Relation p r
 relation' =  SimpleRel . fmap snd
 
-aggregateRelation :: QueryAggregate (Aggregation r) -> Relation p r
+aggregateRelation :: QueryAggregate (Aggregation r) -> Relation () r
 aggregateRelation =  AggregateRel
 
 aggregateRelation' :: QueryAggregate (PlaceHolders p, Aggregation r) -> Relation p r

relational-join/src/Database/Relational/Schema/IBMDB2.hs

@@ -18,8 +18,8 @@ import Database.Record.Instances ()
 
 import Database.Relational.Query.Type (fromRelation)
 import Database.Relational.Query
-  (Query, Relation, query, relation,
-   wheres, (.=.), (!), placeholder, asc, value)
+  (Query, Relation, query, relation',
+   wheres, (.=.), (!), (><), placeholder, asc, value)
 
 import Control.Applicative ((<|>))
 
@@ -62,19 +62,21 @@ getType mapFromSql rec = do
                       else [t| Maybe $(typ) |]
 
 columnsRelationFromTable :: Relation (String, String) Columns
-columnsRelationFromTable =  relation $ do
+columnsRelationFromTable =  relation' $ do
   c <- query columns
-  wheres $ c ! Columns.tabschema' .=. placeholder
-  wheres $ c ! Columns.tabname'   .=. placeholder
+  let (schemaParam, schemaPh) = placeholder
+      (nameParam  , namePh)   = placeholder
+  wheres $ c ! Columns.tabschema' .=. schemaPh
+  wheres $ c ! Columns.tabname'   .=. namePh
   asc $ c ! Columns.colno'
-  return c
+  return (schemaParam >< nameParam, c)
 
 columnsQuerySQL :: Query (String, String) Columns
 columnsQuerySQL =  fromRelation columnsRelationFromTable
 
 
 primaryKeyRelation :: Relation (String, String) String
-primaryKeyRelation =  relation $ do
+primaryKeyRelation =  relation' $ do
   cons  <- query tabconst
   key   <- query keycoluse
   col   <- query columns
@@ -88,10 +90,13 @@ primaryKeyRelation =  relation $ do
   wheres $ cons ! Tabconst.type'     .=. value "P"
   wheres $ cons ! Tabconst.enforced' .=. value "Y"
 
-  wheres $ cons ! Tabconst.tabschema' .=. placeholder
-  wheres $ cons ! Tabconst.tabname'   .=. placeholder
+  let (schemaParam, schemaPh) = placeholder
+      (nameParam  , namePh)   = placeholder
 
-  return $ key ! Keycoluse.colname'
+  wheres $ cons ! Tabconst.tabschema' .=. schemaPh
+  wheres $ cons ! Tabconst.tabname'   .=. namePh
+
+  return   (schemaParam >< nameParam, key ! Keycoluse.colname')
 
 primaryKeyQuerySQL :: Query (String, String) String
 primaryKeyQuerySQL =  fromRelation primaryKeyRelation

relational-join/src/Database/Relational/Schema/PostgreSQL.hs

@@ -24,7 +24,7 @@ import Database.Record.Instances ()
 
 import Database.Relational.Query.Type (fromRelation)
 import Database.Relational.Query
-  (Query, Relation, query, relation, query', relation', expr,
+  (Query, Relation, query, query', relation', expr,
    wheres, (.=.), (.>.), in', values, (!), just,
    placeholder, asc, value, unsafeProjectSql, (><))
 
@@ -96,15 +96,18 @@ getType mapFromSql column@(pgAttr, pgTyp) = do
                       else [t| Maybe $typ |]
 
 relOidRelation :: Relation (String, String) Int32
-relOidRelation = relation $ do
+relOidRelation = relation' $ do
   nsp <- query pgNamespace
   cls <- query pgClass
 
-  wheres $ cls ! Class.relnamespace' .=. nsp ! Namespace.oid'
-  wheres $ nsp ! Namespace.nspname'  .=. placeholder
-  wheres $ cls ! Class.relname'      .=. placeholder
+  let (nspParam, nspPh) = placeholder
+      (relParam, relPh) = placeholder
 
-  return $ cls ! Class.oid'
+  wheres $ cls ! Class.relnamespace' .=. nsp ! Namespace.oid'
+  wheres $ nsp ! Namespace.nspname'  .=. nspPh
+  wheres $ cls ! Class.relname'      .=. relPh
+
+  return   (nspParam >< relParam, cls ! Class.oid')
 
 attributeRelation :: Relation (String, String) PgAttribute
 attributeRelation =  relation' $ do