Index: openacs-4/packages/xowiki/tcl/xowiki-utility-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xowiki/tcl/xowiki-utility-procs.tcl,v
diff -u -r1.37.2.3 -r1.37.2.4
--- openacs-4/packages/xowiki/tcl/xowiki-utility-procs.tcl	2 Sep 2015 10:45:48 -0000	1.37.2.3
+++ openacs-4/packages/xowiki/tcl/xowiki-utility-procs.tcl	11 Feb 2016 10:06:38 -0000	1.37.2.4
@@ -465,6 +465,8 @@
       set tn [$cl table_name]
       set cn ${tn}_fk
       set sc [$cl info superclass]
+      set old_cn ${tn}_[$cl id_column]_fkey
+      ::xo::dc dml drop_constraint "ALTER TABLE $tn DROP constraint IF EXISTS $old_cn"
       ::xo::dc dml drop_constraint "ALTER TABLE $tn DROP constraint IF EXISTS $cn"
       ::xo::dc dml add_constraint  "ALTER TABLE $tn ADD constraint $cn FOREIGN KEY([$cl id_column]) \
         REFERENCES [$sc table_name]([$sc id_column]) ON DELETE CASCADE"