@@ -22,6 +22,7 @@ import Data.Scientific ( Scientific )
2222import Data.Time.Clock ( DiffTime, NominalDiffTime )
2323
2424
25+-- | The class of database types that support the @sum()@ aggregation function.
2526type DBSum :: Type -> Constraint
2627class DBType a => DBSum a
2728instance DBSum Int16