Use schema search path to find the first matching contraint name for SET

CONSTRAINT, rather than affecting all constraints in all schemas (which
is what we used to do).  Also allow schema specifications.

Kris Jurka

doc/src/sgml/ref/set_constraints.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/ref/set_constraints.sgml,v 1.12 2004/09/10 18:39:53 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/ref/set_constraints.sgml,v 1.13 2006/04/27 00:33:32 momjian Exp $ -->
 <refentry id="SQL-SET-CONSTRAINTS">
  <refmeta>
   <refentrytitle id="SQL-SET-CONSTRAINTS-title">SET CONSTRAINTS</refentrytitle>
@@ -45,10 +45,10 @@ SET CONSTRAINTS { ALL | <replaceable class="parameter">name</replaceable> [, ...
 
   <para>
    <command>SET CONSTRAINTS</command> with a list of constraint names changes
-   the mode of just those constraints (which must all be deferrable).  If
-   there are multiple constraints matching any given name, all are affected.
-   <command>SET CONSTRAINTS ALL</command> changes the mode of all deferrable
-   constraints.
+   the mode of just those constraints (which must all be deferrable).  The
+   current schema search path is used to find the first matching name if
+   no schema name is specified.  <command>SET CONSTRAINTS ALL</command> 
+   changes the mode of all deferrable constraints.
   </para>
 
   <para>
@@ -93,13 +93,6 @@ SET CONSTRAINTS { ALL | <replaceable class="parameter">name</replaceable> [, ...
    foreign-key constraints.
   </para>
 
-  <para>
-   The SQL standard says that constraint names appearing in <command>SET
-   CONSTRAINTS</command> can be schema-qualified.  This is not yet
-   supported by <productname>PostgreSQL</productname>: the names must
-   be unqualified, and all constraints matching the command will be
-   affected no matter which schema they are in.
-  </para>
  </refsect1>
 </refentry>
 

src/backend/commands/trigger.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.200 2006/03/05 15:58:25 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.201 2006/04/27 00:33:41 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -24,6 +24,7 @@
 #include "catalog/pg_proc.h"
 #include "catalog/pg_trigger.h"
 #include "catalog/pg_type.h"
+#include "commands/dbcommands.h"
 #include "commands/defrem.h"
 #include "commands/trigger.h"
 #include "executor/executor.h"
@@ -37,6 +38,7 @@
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
+#include "utils/relcache.h"
 #include "utils/syscache.h"
 
 
@@ -2922,65 +2924,133 @@ AfterTriggerSetState(ConstraintsSetStmt *stmt)
 
 		foreach(l, stmt->constraints)
 		{
-			char	   *cname = strVal(lfirst(l));
+			RangeVar   *constraint = lfirst(l);
 			ScanKeyData skey;
 			SysScanDesc tgscan;
 			HeapTuple	htup;
 			bool		found;
+			List	   *namespaceSearchList;
+			ListCell   *namespaceSearchCell;
 
-			/*
-			 * Check that only named constraints are set explicitly
-			 */
-			if (strlen(cname) == 0)
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_NAME),
-					errmsg("unnamed constraints cannot be set explicitly")));
+			if (constraint->catalogname)
+			{
+				if (strcmp(constraint->catalogname, get_database_name(MyDatabaseId)) != 0)
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("cross-database references are not implemented: \"%s.%s.%s\"",
+									constraint->catalogname, constraint->schemaname,
+									constraint->relname)));
+			}
 
-			/*
-			 * Setup to scan pg_trigger by tgconstrname ...
+			/* 
+			 * If we're given the schema name with the constraint, look only
+			 * in that schema.  If given a bare constraint name, use the
+			 * search path to find the first matching constraint.
 			 */
-			ScanKeyInit(&skey,
-						Anum_pg_trigger_tgconstrname,
-						BTEqualStrategyNumber, F_NAMEEQ,
-						PointerGetDatum(cname));
-
-			tgscan = systable_beginscan(tgrel, TriggerConstrNameIndexId, true,
-										SnapshotNow, 1, &skey);
+			if (constraint->schemaname) {
+				Oid namespaceId = LookupExplicitNamespace(constraint->schemaname);
+				namespaceSearchList = list_make1_oid(namespaceId);
+			} else {
+				namespaceSearchList = fetch_search_path(true);
+			}
 
-			/*
-			 * ... and search for the constraint trigger row
-			 */
 			found = false;
-
-			while (HeapTupleIsValid(htup = systable_getnext(tgscan)))
+			foreach(namespaceSearchCell, namespaceSearchList)
 			{
-				Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(htup);
+				Oid searchNamespaceId = lfirst_oid(namespaceSearchCell);
+
+				/*
+				 * Setup to scan pg_trigger by tgconstrname ...
+				 */
+				ScanKeyInit(&skey,
+							Anum_pg_trigger_tgconstrname,
+							BTEqualStrategyNumber, F_NAMEEQ,
+							PointerGetDatum(constraint->relname));
+
+				tgscan = systable_beginscan(tgrel, TriggerConstrNameIndexId, true,
+											SnapshotNow, 1, &skey);
 
 				/*
-				 * If we found some, check that they fit the deferrability but
-				 * skip referential action ones, since they are silently never
-				 * deferrable.
+				 * ... and search for the constraint trigger row
 				 */
-				if (pg_trigger->tgfoid != F_RI_FKEY_RESTRICT_UPD &&
-					pg_trigger->tgfoid != F_RI_FKEY_RESTRICT_DEL &&
-					pg_trigger->tgfoid != F_RI_FKEY_CASCADE_UPD &&
-					pg_trigger->tgfoid != F_RI_FKEY_CASCADE_DEL &&
-					pg_trigger->tgfoid != F_RI_FKEY_SETNULL_UPD &&
-					pg_trigger->tgfoid != F_RI_FKEY_SETNULL_DEL &&
-					pg_trigger->tgfoid != F_RI_FKEY_SETDEFAULT_UPD &&
-					pg_trigger->tgfoid != F_RI_FKEY_SETDEFAULT_DEL)
+				while (HeapTupleIsValid(htup = systable_getnext(tgscan)))
 				{
-					if (stmt->deferred && !pg_trigger->tgdeferrable)
-						ereport(ERROR,
-								(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-								 errmsg("constraint \"%s\" is not deferrable",
-										cname)));
-					oidlist = lappend_oid(oidlist, HeapTupleGetOid(htup));
+					Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(htup);
+					Relation constraintRel;
+					Oid constraintNamespaceId;
+
+					/*
+					 * Foreign key constraints have triggers on both the
+					 * parent and child tables.  Since these tables may be
+					 * in different schemas we must pick the child table
+					 * because that table "owns" the constraint.
+					 *
+					 * Referential triggers on the parent table other than
+					 * NOACTION_DEL and NOACTION_UPD are ignored below, so
+					 * it is possible to not check them here, but it seems
+					 * safer to always check.
+					 */
+					if (pg_trigger->tgfoid == F_RI_FKEY_NOACTION_DEL ||
+						pg_trigger->tgfoid == F_RI_FKEY_NOACTION_UPD ||
+						pg_trigger->tgfoid == F_RI_FKEY_RESTRICT_UPD ||
+						pg_trigger->tgfoid == F_RI_FKEY_RESTRICT_DEL ||
+						pg_trigger->tgfoid == F_RI_FKEY_CASCADE_UPD ||
+						pg_trigger->tgfoid == F_RI_FKEY_CASCADE_DEL ||
+						pg_trigger->tgfoid == F_RI_FKEY_SETNULL_UPD ||
+						pg_trigger->tgfoid == F_RI_FKEY_SETNULL_DEL ||
+						pg_trigger->tgfoid == F_RI_FKEY_SETDEFAULT_UPD ||
+						pg_trigger->tgfoid == F_RI_FKEY_SETDEFAULT_DEL)
+					{
+						constraintRel = RelationIdGetRelation(pg_trigger->tgconstrrelid);
+					} else {
+						constraintRel = RelationIdGetRelation(pg_trigger->tgrelid);
+					}
+					constraintNamespaceId = RelationGetNamespace(constraintRel);
+					RelationClose(constraintRel);
+
+					/*
+					 * If this constraint is not in the schema we're
+					 * currently searching for, keep looking.
+					 */
+					if (constraintNamespaceId != searchNamespaceId)
+						continue;
+
+					/*
+					 * If we found some, check that they fit the deferrability but
+					 * skip referential action ones, since they are silently never
+					 * deferrable.
+					 */
+					if (pg_trigger->tgfoid != F_RI_FKEY_RESTRICT_UPD &&
+						pg_trigger->tgfoid != F_RI_FKEY_RESTRICT_DEL &&
+						pg_trigger->tgfoid != F_RI_FKEY_CASCADE_UPD &&
+						pg_trigger->tgfoid != F_RI_FKEY_CASCADE_DEL &&
+						pg_trigger->tgfoid != F_RI_FKEY_SETNULL_UPD &&
+						pg_trigger->tgfoid != F_RI_FKEY_SETNULL_DEL &&
+						pg_trigger->tgfoid != F_RI_FKEY_SETDEFAULT_UPD &&
+						pg_trigger->tgfoid != F_RI_FKEY_SETDEFAULT_DEL)
+					{
+						if (stmt->deferred && !pg_trigger->tgdeferrable)
+							ereport(ERROR,
+									(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+									 errmsg("constraint \"%s\" is not deferrable",
+											constraint->relname)));
+						oidlist = lappend_oid(oidlist, HeapTupleGetOid(htup));
+					}
+					found = true;
 				}
-				found = true;
+
+				systable_endscan(tgscan);
+
+				/*
+				 * Once we've found a matching constraint we do not search
+				 * later parts of the search path.
+				 */
+				if (found)
+					break;
+
 			}
 
-			systable_endscan(tgscan);
+			list_free(namespaceSearchList);
 
 			/*
 			 * Not found ?
@@ -2989,7 +3059,7 @@ AfterTriggerSetState(ConstraintsSetStmt *stmt)
 				ereport(ERROR,
 						(errcode(ERRCODE_UNDEFINED_OBJECT),
 						 errmsg("constraint \"%s\" does not exist",
-								cname)));
+								constraint->relname)));
 		}
 		heap_close(tgrel, AccessShareLock);
 

src/backend/parser/gram.y

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.542 2006/04/25 14:11:55 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.543 2006/04/27 00:33:45 momjian Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -1283,7 +1283,7 @@ ConstraintsSetStmt:
 
 constraints_set_list:
 			ALL										{ $$ = NIL; }
-			| name_list								{ $$ = $1; }
+			| qualified_name_list					{ $$ = $1; }
 		;
 
 constraints_set_mode:

src/include/nodes/parsenodes.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.307 2006/04/15 17:45:41 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.308 2006/04/27 00:33:46 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1782,7 +1782,7 @@ typedef struct LockStmt
 typedef struct ConstraintsSetStmt
 {
 	NodeTag		type;
-	List	   *constraints;	/* List of names as Value strings */
+	List	   *constraints;	/* List of names as RangeVars */
 	bool		deferred;
 } ConstraintsSetStmt;