diff --git a/Database/Groundhog/MySQL.hs b/Database/Groundhog/MySQL.hs
--- a/Database/Groundhog/MySQL.hs
+++ b/Database/Groundhog/MySQL.hs
@@ -109,6 +109,7 @@
     case x of
       Nothing  -> return Nothing
       Just src -> return (fst $ fromPurePersistValues proxy src)
+  getMigrationPack = fmap (migrationPack . fromJust) getCurrentSchema
 
 withMySQLPool :: (MonadBaseControl IO m, MonadIO m)
               => MySQL.ConnectInfo
@@ -164,7 +165,7 @@
 insert' v = do
   -- constructor number and the rest of the field values
   vals <- toEntityPersistValues' v
-  let e = entityDef v
+  let e = entityDef proxy v
   let constructorNum = fromPrimitivePersistValue proxy (head vals)
 
   liftM fst $ if isSimple (constructors e)
@@ -188,7 +189,7 @@
 insert_' v = do
   -- constructor number and the rest of the field values
   vals <- toEntityPersistValues' v
-  let e = entityDef v
+  let e = entityDef proxy v
   let constructorNum = fromPrimitivePersistValue proxy (head vals)
 
   if isSimple (constructors e)
@@ -208,7 +209,7 @@
 insertIntoConstructorTable withId tName c vals = RenderS query vals' where
   query = "INSERT INTO " <> tName <> columnsValues
   fields = case constrAutoKeyName c of
-    Just idName | withId -> (idName, dbType (0 :: Int64)):constrParams c
+    Just idName | withId -> (idName, dbType proxy (0 :: Int64)):constrParams c
     _                    -> constrParams c
   columnsValues = case foldr (flatten escapeS) [] fields of
     [] -> "() VALUES ()"
@@ -221,7 +222,7 @@
   executeRaw' ("INSERT INTO " <> escapeS mainName <> "()VALUES()") []
   k <- getLastInsertId
   let valuesName = mainName <> delim' <> "values"
-  let fields = [("ord", dbType (0 :: Int)), ("value", dbType (undefined :: a))]
+  let fields = [("ord", dbType proxy (0 :: Int)), ("value", dbType proxy (undefined :: a))]
   let query = "INSERT INTO " <> escapeS valuesName <> "(id," <> renderFields escapeS fields <> ")VALUES(?," <> renderFields (const $ fromChar '?') fields <> ")"
   let go :: Int -> [a] -> DbPersist MySQL m ()
       go n (x:xs) = do
@@ -236,7 +237,7 @@
 getList' k = do
   let mainName = "List" <> delim' <> delim' <> fromString (persistName (undefined :: a))
   let valuesName = mainName <> delim' <> "values"
-  let value = ("value", dbType (undefined :: a))
+  let value = ("value", dbType proxy (undefined :: a))
   let query = "SELECT " <> renderFields escapeS [value] <> " FROM " <> escapeS valuesName <> " WHERE id=? ORDER BY ord"
   queryRaw' query [toPrimitivePersistValue proxy k] $ mapAllRows (liftM fst . fromPersistValues)
 
@@ -274,8 +275,7 @@
 
 migrate' :: (PersistEntity v, MonadBaseControl IO m, MonadIO m, MonadLogger m) => v -> Migration (DbPersist MySQL m)
 migrate' v = do
-  schema <- lift getCurrentSchema
-  let migPack = migrationPack $ fromJust schema
+  migPack <- lift getMigrationPack
   migrateRecursively (migrateSchema migPack) (migrateEntity migPack) (migrateList migPack) v
 
 migrationPack :: (MonadBaseControl IO m, MonadIO m, MonadLogger m) => String -> GM.MigrationPack (DbPersist MySQL m)
@@ -292,9 +292,11 @@
   mainTableId
   defaultPriority
   (\uniques refs -> ([], map AddUnique uniques ++ map AddReference refs))
+  showSqlType
   showColumn
   (showAlterDb currentSchema)
   Restrict
+  Restrict
 
 showColumn :: Column -> String
 showColumn (Column n nu t def) = concat
@@ -356,7 +358,7 @@
       let constraintQuery = "SELECT u.constraint_name, u.column_name FROM information_schema.table_constraints tc INNER JOIN information_schema.key_column_usage u USING (constraint_catalog, constraint_schema, constraint_name, table_schema, table_name) WHERE tc.constraint_type=? AND tc.table_schema=coalesce(?,database()) AND u.table_name=? ORDER BY u.constraint_name, u.column_name"
       uniqConstraints <- queryRaw' constraintQuery [toPrimitivePersistValue proxy ("UNIQUE" :: String), toPrimitivePersistValue proxy schema, toPrimitivePersistValue proxy name] (mapAllRows $ return . fst . fromPurePersistValues proxy)
       uniqPrimary <- queryRaw' constraintQuery [toPrimitivePersistValue proxy ("PRIMARY KEY" :: String), toPrimitivePersistValue proxy schema, toPrimitivePersistValue proxy name] (mapAllRows $ return . fst . fromPurePersistValues proxy)
-      let mkUniqs typ = map (\us -> UniqueDef' (fst $ head us) typ (map snd us)) . groupBy ((==) `on` fst)
+      let mkUniqs typ = map (\us -> UniqueDef (fst $ head us) typ (map (Left . snd) us)) . groupBy ((==) `on` fst)
           isAutoincremented = case filter (\c -> colName (fst c) `elem` map snd uniqPrimary) cols of
                                 [(c, extra)] -> colType c `elem` [DbInt32, DbInt64] && "auto_increment" `isInfixOf` (extra :: String)
                                 _ -> False
@@ -432,31 +434,31 @@
       ])]
     f _ = []
   (updates, other) = partition (\a -> case a of UpdateValue _ -> True; _ -> False) alts
-showAlterTable _ table (AddUnique (UniqueDef' uName UniqueConstraint cols)) = [(False, defaultPriority, concat
+showAlterTable _ table (AddUnique (UniqueDef uName UniqueConstraint cols)) = [(False, defaultPriority, concat
   [ "ALTER TABLE "
   , table
   , " ADD"
   , maybe "" ((" CONSTRAINT " ++) . escape) uName
   , " UNIQUE("
-  , intercalate "," $ map escape cols
+  , intercalate "," $ map (either escape id) cols
   , ")"
   ])]
-showAlterTable _ table (AddUnique (UniqueDef' uName UniqueIndex cols)) = [(False, defaultPriority, concat
+showAlterTable _ table (AddUnique (UniqueDef uName UniqueIndex cols)) = [(False, defaultPriority, concat
   [ "CREATE UNIQUE INDEX "
   , maybe (error $ "showAlterTable: index for table " ++ table ++ " does not have a name") escape uName
   , " ON "
   , table
   , "("
-  , intercalate "," $ map escape cols
+  , intercalate "," $ map (either escape id) cols
   , ")"
   ])]
-showAlterTable _ table (AddUnique (UniqueDef' uName (UniquePrimary _) cols)) = [(False, defaultPriority, concat
+showAlterTable _ table (AddUnique (UniqueDef uName (UniquePrimary _) cols)) = [(False, defaultPriority, concat
   [ "ALTER TABLE "
   , table
   , " ADD"
   , maybe "" ((" CONSTRAINT " ++) . escape) uName
   , " PRIMARY KEY("
-  , intercalate "," $ map escape cols
+  , intercalate "," $ map (either escape id) cols
   , ")"
   ])]
 showAlterTable _ table (DropConstraint uName) = [(False, defaultPriority, concat
@@ -502,7 +504,7 @@
   "time" -> DbTime
   _ | typ `elem` ["datetime", "timestamp"] -> DbDayTime
   _ | typ `elem` ["date", "newdate", "year"] -> DbDay
-  _ -> DbOther $ OtherTypeDef $ const colTyp
+  _ -> DbOther $ OtherTypeDef [Left colTyp]
   ) where
     numAttrs = (numeric_precision, numeric_scale)
 
@@ -518,12 +520,11 @@
   DbDayTime -> "DATETIME"
   DbDayTimeZoned -> "VARCHAR(50) CHARACTER SET utf8"
   DbBlob -> "BLOB"
-  DbOther (OtherTypeDef f) -> f showSqlType
-  DbAutoKey -> showSqlType DbInt64
+  DbOther (OtherTypeDef ts) -> concatMap (either id showSqlType) ts
 
-compareUniqs :: UniqueDef' -> UniqueDef' -> Bool
-compareUniqs (UniqueDef' _ (UniquePrimary _) cols1) (UniqueDef' _ (UniquePrimary _) cols2) = haveSameElems (==) cols1 cols2
-compareUniqs (UniqueDef' name1 _ cols1) (UniqueDef' name2 _ cols2) = fromMaybe True (liftM2 (==) name1 name2) && haveSameElems (==) cols1 cols2
+compareUniqs :: UniqueDefInfo -> UniqueDefInfo -> Bool
+compareUniqs (UniqueDef _ (UniquePrimary _) cols1) (UniqueDef _ (UniquePrimary _) cols2) = haveSameElems (==) cols1 cols2
+compareUniqs (UniqueDef name1 _ cols1) (UniqueDef name2 _ cols2) = fromMaybe True (liftM2 (==) name1 name2) && haveSameElems (==) cols1 cols2
 
 compareRefs :: String -> (Maybe String, Reference) -> (Maybe String, Reference) -> Bool
 compareRefs currentSchema (_, Reference sch1 tbl1 pairs1 onDel1 onUpd1) (_, Reference sch2 tbl2 pairs2 onDel2 onUpd2) =
@@ -537,7 +538,7 @@
 compareTypes :: DbTypePrimitive -> DbTypePrimitive -> Bool
 compareTypes type1 type2 = f type1 == f type2 where
   f = map toUpper . showSqlType . hack
-  hack DbDayTimeZoned = DbOther $ OtherTypeDef $ const "VARCHAR(50)"
+  hack DbDayTimeZoned = DbOther $ OtherTypeDef [Left "VARCHAR(50)"]
   hack t = t
 
 compareDefaults :: String -> String -> Bool
diff --git a/changelog b/changelog
--- a/changelog
+++ b/changelog
@@ -1,3 +1,7 @@
+0.6.0
+* Entity and fields descriptions are parameterized so that they can be promoted
+* Entity and fields descriptions are dependent on database proxy. It allows to use different types depending on a database, for example, the same type can be array[] in PostgreSQL and varchar elsewhere
+
 0.5.1
 * Add getCurrentSchema function into SchemaAnalyzer
 
diff --git a/groundhog-mysql.cabal b/groundhog-mysql.cabal
--- a/groundhog-mysql.cabal
+++ b/groundhog-mysql.cabal
@@ -1,5 +1,5 @@
 name:            groundhog-mysql
-version:         0.5.1
+version:         0.6.0
 license:         BSD3
 license-file:    LICENSE
 author:          Boris Lykah <lykahb@gmail.com>
@@ -20,7 +20,7 @@
                    , mysql                    >= 0.1.1.3   && < 0.2
                    , bytestring               >= 0.9
                    , transformers             >= 0.2.1     && < 0.5
-                   , groundhog                >= 0.5.0     && < 0.6.0
+                   , groundhog                >= 0.6       && < 0.7
                    , monad-control            >= 0.3       && < 0.4
                    , monad-logger             >= 0.3       && < 0.4
                    , containers               >= 0.2