diff lib/ur/basis.urs @ 1421:3dab4696d116

Subqueries may always return NULL
author Adam Chlipala <adam@chlipala.net>
date Thu, 03 Feb 2011 21:04:12 -0500
parents 00b79f39be25
children 541673c3161d
line wrap: on
line diff
--- a/lib/ur/basis.urs	Thu Feb 03 11:12:48 2011 -0500
+++ b/lib/ur/basis.urs	Thu Feb 03 21:04:12 2011 -0500
@@ -529,9 +529,10 @@
                    -> sql_exp tables agg exps t
                    -> sql_exp tables agg exps (option t)
 
-val sql_subquery : tables ::: {{Type}} -> agg ::: {{Type}} -> exps ::: {Type} -> nm ::: Name -> t ::: Type
+val sql_subquery : tables ::: {{Type}} -> agg ::: {{Type}} -> exps ::: {Type} -> nm ::: Name -> t ::: Type -> nt ::: Type
+                   -> nullify t nt
                    -> sql_query tables agg [] [nm = t]
-                   -> sql_exp tables agg exps t
+                   -> sql_exp tables agg exps nt
 
 (*** Executing queries *)