src/TSN/Database.hs

   1 -- | Standalone database functions for dealing with Groundhog types.
   2 --
   3 module TSN.Database ( insert_or_select )
   4 where
   5
   6 import Database.Groundhog ( AutoKey, insertByAll )
   7 import Database.Groundhog.Core ( PersistBackend, PersistEntity )
   8
   9
  10 -- | Attempt to insert the given object returning its new primary
  11 --   key. If any unique constraints would be violated, instead return
  12 --   the primary key of the existing record that caused the collision.
  13 insert_or_select :: (PersistBackend m, PersistEntity a)
  14                  => a
  15                  -> m (AutoKey a)
  16 insert_or_select x = do
  17   tmp <- insertByAll x
  18   return $ (either id id) tmp