diff --git a/Database/Groundhog/Postgresql.hs b/Database/Groundhog/Postgresql.hs
--- a/Database/Groundhog/Postgresql.hs
+++ b/Database/Groundhog/Postgresql.hs
@@ -7,10 +7,13 @@
     , Postgresql(..)
     , module Database.Groundhog
     , module Database.Groundhog.Generic.Sql.Functions
+    , explicitType
+    , castType
     ) where
 
 import Database.Groundhog
 import Database.Groundhog.Core
+import Database.Groundhog.Expression
 import Database.Groundhog.Generic
 import Database.Groundhog.Generic.Migration hiding (MigrationPack(..))
 import qualified Database.Groundhog.Generic.Migration as GM
@@ -63,13 +66,15 @@
   insertBy u v = H.insertBy escapeS queryRawTyped' True u v
   insertByAll v = H.insertByAll escapeS queryRawTyped' True v
   replace k v = H.replace escapeS queryRawTyped' executeRaw' (insertIntoConstructorTable False) k v
+  replaceBy k v = H.replaceBy escapeS executeRaw' k v
   select options = H.select escapeS queryRawTyped' "" renderCond' options
   selectAll = H.selectAll escapeS queryRawTyped'
   get k = H.get escapeS queryRawTyped' k
   getBy k = H.getBy escapeS queryRawTyped' k
   update upds cond = H.update escapeS executeRaw' renderCond' upds cond
   delete cond = H.delete escapeS executeRaw' renderCond' cond
-  deleteByKey k = H.deleteByKey escapeS executeRaw' k
+  deleteBy k = H.deleteBy escapeS executeRaw' k
+  deleteAll v = H.deleteAll escapeS executeRaw' v
   count cond = H.count escapeS queryRawTyped' renderCond' cond
   countAll fakeV = H.countAll escapeS queryRawTyped' fakeV
   project p options = H.project escapeS queryRawTyped' "" renderCond' p options
@@ -325,7 +330,7 @@
             else [DropTrigger schema trigName schema name, addTrigger])
   return (trigExisted, funcMig ++ trigMig)
       
--- | Table name and a  list of field names and according delete statements
+-- | Table name and a list of field names and according delete statements
 -- assume that this function is called only for ephemeral fields
 migTriggerOnUpdate :: (MonadBaseControl IO m, MonadIO m, MonadLogger m) => Maybe String -> String -> [(String, String)] -> DbPersist Postgresql m [(Bool, [AlterDB])]
 migTriggerOnUpdate schema name dels = forM dels $ \(fieldName, del) -> do
@@ -737,3 +742,17 @@
 
 withSchema :: Maybe String -> String -> String
 withSchema sch name = maybe "" (\x -> escape x ++ ".") sch ++ escape name
+
+
+-- | Put explicit type for expression. It is useful for values which are defaulted to a wrong type.
+-- For example, a literal Int from a 64bit machine can be defaulted to a 32bit int by Postgresql. 
+-- Also a value entered as an external string (geometry, arrays and other complex types have this representation) may need an explicit type. 
+explicitType :: (Expression Postgresql r a, PersistField a) => a -> Expr Postgresql r a
+explicitType a = castType a t where
+  t = case dbType a of
+    DbTypePrimitive t' _ _ _ -> showSqlType t'
+    _ -> error "explicitType: type is not primitive"
+
+-- | Casts expression to a type. @castType value \"INT\"@ results in @value::INT@.
+castType :: Expression Postgresql r a => a -> String -> Expr Postgresql r a
+castType a t = Expr $ Snippet $ \esc _ -> ["(" <> renderExpr esc (toExpr a) <> ")::" <> fromString t] where
diff --git a/Database/Groundhog/Postgresql/Array.hs b/Database/Groundhog/Postgresql/Array.hs
--- a/Database/Groundhog/Postgresql/Array.hs
+++ b/Database/Groundhog/Postgresql/Array.hs
@@ -131,13 +131,13 @@
 (!:) arr (i1, i2) = Expr $ Snippet $ \esc _ -> [renderExpr esc (toExpr arr) <> "[" <> renderExpr esc (toExpr i1) <> ":" <> renderExpr esc (toExpr i2) <> "]"]
 
 prepend :: (ExpressionOf Postgresql r a elem, ExpressionOf Postgresql r b (Array elem)) => a -> b -> Expr Postgresql r (Array elem)
-prepend a b = Expr $ operator 50 "||" a b
+prepend a b = Expr $ function "array_prepend" [toExpr a, toExpr b]
 
 append :: (ExpressionOf Postgresql r a (Array elem), ExpressionOf Postgresql r b elem) => a -> b -> Expr Postgresql r (Array elem)
-append a b = Expr $ operator 50 "||" a b
+append a b = Expr $ function "array_append" [toExpr a, toExpr b]
 
 arrayCat :: (ExpressionOf Postgresql r a (Array elem), ExpressionOf Postgresql r b (Array elem)) => a -> b -> Expr Postgresql r (Array elem)
-arrayCat a b = Expr $ operator 50 "||" a b
+arrayCat a b = Expr $ function "array_cat" [toExpr a, toExpr b]
 
 arrayDims :: (ExpressionOf Postgresql r a (Array elem)) => a -> Expr Postgresql r String
 arrayDims arr = Expr $ function "array_dims" [toExpr arr]
diff --git a/groundhog-postgresql.cabal b/groundhog-postgresql.cabal
--- a/groundhog-postgresql.cabal
+++ b/groundhog-postgresql.cabal
@@ -1,5 +1,5 @@
 name:            groundhog-postgresql
-version:         0.4.0.3
+version:         0.4.1
 license:         BSD3
 license-file:    LICENSE
 author:          Boris Lykah <lykahb@gmail.com>
@@ -18,7 +18,7 @@
                    , bytestring              >= 0.9
                    , blaze-builder           >= 0.3.0.0
                    , transformers            >= 0.2.1
-                   , groundhog               >= 0.4.0.3   && < 0.5.0
+                   , groundhog               >= 0.4.1     && < 0.5.0
                    , monad-control           >= 0.3
                    , monad-logger            >= 0.3
                    , containers              >= 0.2