Index: openacs-4/packages/acs-kernel/sql/postgresql/rel-constraints-create.sql
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-kernel/sql/postgresql/rel-constraints-create.sql,v
diff -u -r1.8 -r1.9
--- openacs-4/packages/acs-kernel/sql/postgresql/rel-constraints-create.sql	18 Apr 2001 05:20:54 -0000	1.8
+++ openacs-4/packages/acs-kernel/sql/postgresql/rel-constraints-create.sql	20 Apr 2001 02:03:49 -0000	1.9
@@ -74,17 +74,32 @@
 declare
         v_parent_sk     varchar;
         max_key         varchar;
+        has_parents_p   boolean;
 begin
-        select max(tree_sortkey) into max_key 
+        select count(*) > 0 into has_parents_p
           from rel_constraints 
-         where required_rel_segment = new.required_rel_segment
-           and rel_side = new.rel_side;
-
-        select coalesce(max(tree_sortkey),'''') into v_parent_sk 
-          from rel_constraints 
          where rel_segment = new.required_rel_segment
            and rel_side = new.rel_side;
+       
+        if has_parents_p then 
+           select max(tree_sortkey) into max_key 
+             from rel_constraints 
+            where required_rel_segment = new.required_rel_segment
+              and rel_side = new.rel_side;
 
+           select coalesce(max(tree_sortkey),'''') into v_parent_sk 
+             from rel_constraints 
+            where rel_segment = new.required_rel_segment
+              and rel_side = new.rel_side;
+        else 
+           select max(tree_sortkey) into max_key 
+             from rel_constraints 
+            where rel_side = new.rel_side 
+              and tree_level(tree_sortkey) = 1;
+
+           v_parent_sk := '''';
+        end if;
+
         new.tree_sortkey := v_parent_sk || ''/'' || tree_next_key(max_key);
 
         return new;
@@ -668,13 +683,15 @@
 -- It seems correct, but it might be bogus.
 -- DCW 2001-03-14.
 
+-- drop view rc_segment_dependency_levels;
 create view rc_segment_dependency_levels as
              select rc1.rel_segment as segment_id, 
                     max(tree_level(rc1.tree_sortkey)) as dependency_level
                from rel_constraints rc1, rel_constraints rc2
               where ('two' = (select rel_side 
                                 from rel_constraints 
-                               where rel_segment = rc1.required_rel_segment)
+                               where rel_segment = rc1.required_rel_segment
+                                 and rel_side = rc1.rel_side)
                      or rc1.rel_segment = rc2.rel_segment)     
                 and rc1.tree_sortkey like rc2.tree_sortkey || '%'
            group by segment_id;