Update TODO list.

doc/TODO

 TODO list for PostgreSQL
 ========================
-Last updated:		Sat Apr 22 16:33:07 EDT 2000
+Last updated:		Fri Apr 28 10:44:19 EDT 2000
 
 Current maintainer:	Bruce Momjian (pgman@candle.pha.pa.us)
 
@@ -51,6 +51,8 @@ MISC
   another backend.  Might  lead  to  MVCC  inside  of  syscache
 * Permission to UPDATE table allows DELETE also
 * Some database schema's are not dumpable;  do dumps in oid order
+
+
 ENHANCEMENTS
 ------------
 
@@ -171,6 +173,12 @@ MISC
 * Allow BLCKSZ <= 64k, not <= 32k
 * redesign UNION structures to have separarate target lists
 * Allow multi-level query trees for INSERT INTO ... SELECT
+* Check that primary key exists at foreign key definition time
+* Prevent column dropping if column is used by foreign key
+* Propagate column or table renaming to foreign key constraints
+* Emit a warning at foreign key creation time if no UNIQUE index
+  exists on referenced primary key attributes
+
 
 PERFORMANCE
 -----------
@@ -218,6 +226,7 @@ MISC
 * prevent labels from being output for stored rules (Tom)
 * allow configuration of maximum number of open files
 
+
 SOURCE CODE
 -----------
 * Add use of 'const' for variables in source tree