Index: openacs-4/packages/acs-content-repository/sql/postgresql/upgrade/upgrade-5.9.0d2-5.9.0d3.sql
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-content-repository/sql/postgresql/upgrade/upgrade-5.9.0d2-5.9.0d3.sql,v
diff -u -r1.2 -r1.3
--- openacs-4/packages/acs-content-repository/sql/postgresql/upgrade/upgrade-5.9.0d2-5.9.0d3.sql	3 May 2015 12:40:38 -0000	1.2
+++ openacs-4/packages/acs-content-repository/sql/postgresql/upgrade/upgrade-5.9.0d2-5.9.0d3.sql	7 Aug 2017 23:47:47 -0000	1.3
@@ -26,38 +26,38 @@
 
 -- constraints from acs-content-repository/sql/postgresql/content-revision.sql
 
-ALTER TABLE cr_item_publish_audit DROP CONSTRAINT cr_item_publish_audit_orev_fk;
+ALTER TABLE cr_item_publish_audit DROP CONSTRAINT IF EXISTS cr_item_publish_audit_orev_fk;
 ALTER TABLE cr_item_publish_audit ADD CONSTRAINT cr_item_publish_audit_orev_fk
 FOREIGN KEY (old_revision) REFERENCES cr_revisions(revision_id) ON DELETE CASCADE;
 
-ALTER TABLE cr_item_publish_audit DROP CONSTRAINT cr_item_publish_audit_nrev_fk;
+ALTER TABLE cr_item_publish_audit DROP CONSTRAINT IF EXISTS cr_item_publish_audit_nrev_fk;
 ALTER TABLE cr_item_publish_audit ADD CONSTRAINT cr_item_publish_audit_nrev_fk
 FOREIGN KEY (new_revision) REFERENCES cr_revisions(revision_id) ON DELETE CASCADE;
 
 
 -- constraints from acs-content-repository/sql/postgresql/content-item.sql
 
-ALTER TABLE cr_release_periods DROP CONSTRAINT cr_release_periods_item_id_fk;
+ALTER TABLE cr_release_periods DROP CONSTRAINT IF EXISTS cr_release_periods_item_id_fk;
 ALTER TABLE cr_release_periods ADD CONSTRAINT cr_release_periods_item_id_fk
 FOREIGN KEY (item_id) REFERENCES cr_items(item_id) ON DELETE CASCADE;
 
-ALTER TABLE cr_item_publish_audit DROP CONSTRAINT cr_item_publish_audit_item_fk;
+ALTER TABLE cr_item_publish_audit DROP CONSTRAINT IF EXISTS  cr_item_publish_audit_item_fk;
 ALTER TABLE cr_item_publish_audit ADD CONSTRAINT cr_item_publish_audit_item_fk
 FOREIGN KEY (item_id) REFERENCES cr_items(item_id) ON DELETE CASCADE;
 
-ALTER TABLE cr_item_template_map DROP CONSTRAINT cr_item_template_map_item_fk;
+ALTER TABLE cr_item_template_map DROP CONSTRAINT IF EXISTS cr_item_template_map_item_fk;
 ALTER TABLE cr_item_template_map ADD CONSTRAINT cr_item_template_map_item_fk
 FOREIGN KEY (item_id) REFERENCES cr_items(item_id) ON DELETE CASCADE;
 
-ALTER TABLE cr_item_keyword_map DROP CONSTRAINT cr_item_keyword_map_item_id_fk;
+ALTER TABLE cr_item_keyword_map DROP CONSTRAINT IF EXISTS cr_item_keyword_map_item_id_fk;
 ALTER TABLE cr_item_keyword_map ADD CONSTRAINT cr_item_keyword_map_item_id_fk
 FOREIGN KEY (item_id) REFERENCES cr_items(item_id) ON DELETE CASCADE;
 
-ALTER TABLE cr_items DROP CONSTRAINT cr_items_latest_fk;
+ALTER TABLE cr_items DROP CONSTRAINT IF EXISTS cr_items_latest_fk;
 ALTER TABLE cr_items ADD CONSTRAINT cr_items_latest_fk
 FOREIGN KEY (latest_revision) REFERENCES cr_revisions(revision_id) on delete set null;
 
-ALTER TABLE cr_items DROP CONSTRAINT cr_items_live_fk;
+ALTER TABLE cr_items DROP CONSTRAINT IF EXISTS cr_items_live_fk;
 ALTER TABLE cr_items ADD CONSTRAINT cr_items_live_fk
 FOREIGN KEY (live_revision) REFERENCES cr_revisions(revision_id) on delete set null;
 
@@ -149,7 +149,7 @@
   --
   -- The following loop could be dropped / replaced by a cascade
   -- operation, when proper foreign keys are used along the
-  -- inheritence path.
+  -- inheritance path.
   --
   for v_revision_val in select revision_id 
                         from   cr_revisions