+instance DbImport Message where
+ dbmigrate _ =
+ runMigration defaultMigrationLogger $ do
+ migrate (undefined :: NewsTeam)
+ migrate (undefined :: NewsLocation)
+ migrate (undefined :: News)
+ migrate (undefined :: News_NewsTeam)
+ migrate (undefined :: News_NewsLocation)
+
+ dbimport message = do
+ -- Insert the message and acquire its primary key (unique ID)
+ news_id <- insert_xml message
+
+ -- And insert each one into its own table. We use insertByAll_xml
+ -- because we know that most teams will already exist, and we
+ -- want to get back a Left (id) for the existing team when
+ -- there's a collision. In fact, if the insert succeeds, we'll
+ -- get a Right (id) back, so we can disregard the Either
+ -- constructor entirely. That's what the (either id id) does.
+ either_nt_ids <- mapM insertByAll_xml (xml_teams message)
+ let nt_ids = map (either id id) either_nt_ids
+
+ -- Now that the teams have been inserted, create
+ -- news__news_team records mapping beween the two.
+ let news_news_teams = map (News_NewsTeam news_id) nt_ids
+ mapM_ insert_ news_news_teams
+
+ -- Do all of that over again for the NewsLocations.
+ either_loc_ids <- mapM insertByAll_xml (xml_locations message)
+ let loc_ids = map (either id id) either_loc_ids
+ let news_news_locations = map (News_NewsLocation news_id) loc_ids
+ mapM_ insert_ news_news_locations
+
+ return ImportSucceeded
+
+
+-- These types don't have special XML representations or field name
+-- collisions so we use the defaultCodegenConfig and give their fields
+-- nice simple names.
+mkPersist defaultCodegenConfig [groundhog|