Merge the Constraint and FkConstraint node types into a single type.

This was foreseen to be a good idea long ago, but nobody had got round
to doing it.  The recent patch for deferred unique constraints made
transformConstraintAttrs() ugly enough that I decided it was time.
This change will also greatly simplify parsing of deferred CHECK constraints,
if anyone ever gets around to implementing that.

While at it, add a location field to Constraint, and use that to provide
an error cursor for some of the constraint-related error messages.

src/backend/catalog/heap.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/heap.c,v 1.355 2009/07/28 02:56:29 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/heap.c,v 1.356 2009/07/30 02:45:36 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -1870,11 +1870,11 @@ AddRelationNewConstraints(Relation rel,
 		/*
 		 * Check name uniqueness, or generate a name if none was given.
 		 */
-		if (cdef->name != NULL)
+		if (cdef->conname != NULL)
 		{
 			ListCell   *cell2;
 
-			ccname = cdef->name;
+			ccname = cdef->conname;
 			/* Check against other new constraints */
 			/* Needed because we don't do CommandCounterIncrement in loop */
 			foreach(cell2, checknames)

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 1.250 2009/07/29 20:56:18 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/trigger.c,v 1.251 2009/07/30 02:45:36 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -607,12 +607,14 @@ ConvertTriggerToFK(CreateTrigStmt *stmt, Oid funcoid)
 		/* OK, we have a set, so make the FK constraint ALTER TABLE cmd */
 		AlterTableStmt *atstmt = makeNode(AlterTableStmt);
 		AlterTableCmd *atcmd = makeNode(AlterTableCmd);
-		FkConstraint *fkcon = makeNode(FkConstraint);
+		Constraint *fkcon = makeNode(Constraint);
 
 		ereport(NOTICE,
 				(errmsg("converting trigger group into constraint \"%s\" %s",
 						constr_name, buf.data),
 				 errdetail("%s", _(funcdescr[funcnum]))));
+		fkcon->contype = CONSTR_FOREIGN;
+		fkcon->location = -1;
 		if (funcnum == 2)
 		{
 			/* This trigger is on the FK table */
@@ -642,9 +644,9 @@ ConvertTriggerToFK(CreateTrigStmt *stmt, Oid funcoid)
 		atcmd->subtype = AT_AddConstraint;
 		atcmd->def = (Node *) fkcon;
 		if (strcmp(constr_name, "<unnamed>") == 0)
-			fkcon->constr_name = NULL;
+			fkcon->conname = NULL;
 		else
-			fkcon->constr_name = constr_name;
+			fkcon->conname = constr_name;
 		fkcon->fk_attrs = fk_attrs;
 		fkcon->pk_attrs = pk_attrs;
 		fkcon->fk_matchtype = fk_matchtype;

src/backend/commands/typecmds.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/typecmds.c,v 1.136 2009/07/28 02:56:30 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/typecmds.c,v 1.137 2009/07/30 02:45:36 tgl Exp $
  *
  * DESCRIPTION
  *	  The "DefineFoo" routines take the parse tree and pick out the
@@ -867,22 +867,11 @@ DefineDomain(CreateDomainStmt *stmt)
 	 */
 	foreach(listptr, schema)
 	{
-		Node	   *newConstraint = lfirst(listptr);
-		Constraint *constr;
-
-		/* Check for unsupported constraint types */
-		if (IsA(newConstraint, FkConstraint))
-			ereport(ERROR,
-					(errcode(ERRCODE_SYNTAX_ERROR),
-				errmsg("foreign key constraints not possible for domains")));
+		Constraint *constr = lfirst(listptr);
 
-		/* otherwise it should be a plain Constraint */
-		if (!IsA(newConstraint, Constraint))
+		if (!IsA(constr, Constraint))
 			elog(ERROR, "unrecognized node type: %d",
-				 (int) nodeTag(newConstraint));
-
-		constr = (Constraint *) newConstraint;
-
+				 (int) nodeTag(constr));
 		switch (constr->contype)
 		{
 			case CONSTR_DEFAULT:
@@ -995,6 +984,12 @@ DefineDomain(CreateDomainStmt *stmt)
 				errmsg("primary key constraints not possible for domains")));
 				break;
 
+			case CONSTR_FOREIGN:
+				ereport(ERROR,
+						(errcode(ERRCODE_SYNTAX_ERROR),
+				errmsg("foreign key constraints not possible for domains")));
+				break;
+
 			case CONSTR_ATTR_DEFERRABLE:
 			case CONSTR_ATTR_NOT_DEFERRABLE:
 			case CONSTR_ATTR_DEFERRED:
@@ -1849,13 +1844,6 @@ AlterDomainAddConstraint(List *names, Node *newConstraint)
 	/* Check it's a domain and check user has permission for ALTER DOMAIN */
 	checkDomainOwner(tup, typename);
 
-	/* Check for unsupported constraint types */
-	if (IsA(newConstraint, FkConstraint))
-		ereport(ERROR,
-				(errcode(ERRCODE_SYNTAX_ERROR),
-				 errmsg("foreign key constraints not possible for domains")));
-
-	/* otherwise it should be a plain Constraint */
 	if (!IsA(newConstraint, Constraint))
 		elog(ERROR, "unrecognized node type: %d",
 			 (int) nodeTag(newConstraint));
@@ -1880,6 +1868,12 @@ AlterDomainAddConstraint(List *names, Node *newConstraint)
 				errmsg("primary key constraints not possible for domains")));
 			break;
 
+		case CONSTR_FOREIGN:
+			ereport(ERROR,
+					(errcode(ERRCODE_SYNTAX_ERROR),
+				errmsg("foreign key constraints not possible for domains")));
+			break;
+
 		case CONSTR_ATTR_DEFERRABLE:
 		case CONSTR_ATTR_NOT_DEFERRABLE:
 		case CONSTR_ATTR_DEFERRED:
@@ -2188,23 +2182,23 @@ domainAddConstraint(Oid domainOid, Oid domainNamespace, Oid baseTypeOid,
 	/*
 	 * Assign or validate constraint name
 	 */
-	if (constr->name)
+	if (constr->conname)
 	{
 		if (ConstraintNameIsUsed(CONSTRAINT_DOMAIN,
 								 domainOid,
 								 domainNamespace,
-								 constr->name))
+								 constr->conname))
 			ereport(ERROR,
 					(errcode(ERRCODE_DUPLICATE_OBJECT),
 				 errmsg("constraint \"%s\" for domain \"%s\" already exists",
-						constr->name, domainName)));
+						constr->conname, domainName)));
 	}
 	else
-		constr->name = ChooseConstraintName(domainName,
-											NULL,
-											"check",
-											domainNamespace,
-											NIL);
+		constr->conname = ChooseConstraintName(domainName,
+											   NULL,
+											   "check",
+											   domainNamespace,
+											   NIL);
 
 	/*
 	 * Convert the A_EXPR in raw_expr into an EXPR
@@ -2284,7 +2278,7 @@ domainAddConstraint(Oid domainOid, Oid domainNamespace, Oid baseTypeOid,
 	/*
 	 * Store the constraint in pg_constraint
 	 */
-	CreateConstraintEntry(constr->name, /* Constraint Name */
+	CreateConstraintEntry(constr->conname,		/* Constraint Name */
 						  domainNamespace,		/* namespace */
 						  CONSTRAINT_CHECK,		/* Constraint Type */
 						  false,	/* Is Deferrable */

src/backend/nodes/copyfuncs.c

@@ -15,7 +15,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.436 2009/07/29 20:56:19 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.437 2009/07/30 02:45:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1738,25 +1738,6 @@ _copyRangeTblEntry(RangeTblEntry *from)
 	return newnode;
 }
 
-static FkConstraint *
-_copyFkConstraint(FkConstraint *from)
-{
-	FkConstraint *newnode = makeNode(FkConstraint);
-
-	COPY_STRING_FIELD(constr_name);
-	COPY_NODE_FIELD(pktable);
-	COPY_NODE_FIELD(fk_attrs);
-	COPY_NODE_FIELD(pk_attrs);
-	COPY_SCALAR_FIELD(fk_matchtype);
-	COPY_SCALAR_FIELD(fk_upd_action);
-	COPY_SCALAR_FIELD(fk_del_action);
-	COPY_SCALAR_FIELD(deferrable);
-	COPY_SCALAR_FIELD(initdeferred);
-	COPY_SCALAR_FIELD(skip_validation);
-
-	return newnode;
-}
-
 static SortGroupClause *
 _copySortGroupClause(SortGroupClause *from)
 {
@@ -2085,14 +2066,22 @@ _copyConstraint(Constraint *from)
 	Constraint *newnode = makeNode(Constraint);
 
 	COPY_SCALAR_FIELD(contype);
-	COPY_STRING_FIELD(name);
+	COPY_STRING_FIELD(conname);
+	COPY_SCALAR_FIELD(deferrable);
+	COPY_SCALAR_FIELD(initdeferred);
+	COPY_LOCATION_FIELD(location);
 	COPY_NODE_FIELD(raw_expr);
 	COPY_STRING_FIELD(cooked_expr);
 	COPY_NODE_FIELD(keys);
 	COPY_NODE_FIELD(options);
 	COPY_STRING_FIELD(indexspace);
-	COPY_SCALAR_FIELD(deferrable);
-	COPY_SCALAR_FIELD(initdeferred);
+	COPY_NODE_FIELD(pktable);
+	COPY_NODE_FIELD(fk_attrs);
+	COPY_NODE_FIELD(pk_attrs);
+	COPY_SCALAR_FIELD(fk_matchtype);
+	COPY_SCALAR_FIELD(fk_upd_action);
+	COPY_SCALAR_FIELD(fk_del_action);
+	COPY_SCALAR_FIELD(skip_validation);
 
 	return newnode;
 }
@@ -4082,9 +4071,6 @@ copyObject(void *from)
 		case T_CommonTableExpr:
 			retval = _copyCommonTableExpr(from);
 			break;
-		case T_FkConstraint:
-			retval = _copyFkConstraint(from);
-			break;
 		case T_PrivGrantee:
 			retval = _copyPrivGrantee(from);
 			break;

src/backend/nodes/equalfuncs.c

@@ -22,7 +22,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.359 2009/07/29 20:56:19 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.360 2009/07/30 02:45:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2064,14 +2064,22 @@ static bool
 _equalConstraint(Constraint *a, Constraint *b)
 {
 	COMPARE_SCALAR_FIELD(contype);
-	COMPARE_STRING_FIELD(name);
+	COMPARE_STRING_FIELD(conname);
+	COMPARE_SCALAR_FIELD(deferrable);
+	COMPARE_SCALAR_FIELD(initdeferred);
+	COMPARE_LOCATION_FIELD(location);
 	COMPARE_NODE_FIELD(raw_expr);
 	COMPARE_STRING_FIELD(cooked_expr);
 	COMPARE_NODE_FIELD(keys);
 	COMPARE_NODE_FIELD(options);
 	COMPARE_STRING_FIELD(indexspace);
-	COMPARE_SCALAR_FIELD(deferrable);
-	COMPARE_SCALAR_FIELD(initdeferred);
+	COMPARE_NODE_FIELD(pktable);
+	COMPARE_NODE_FIELD(fk_attrs);
+	COMPARE_NODE_FIELD(pk_attrs);
+	COMPARE_SCALAR_FIELD(fk_matchtype);
+	COMPARE_SCALAR_FIELD(fk_upd_action);
+	COMPARE_SCALAR_FIELD(fk_del_action);
+	COMPARE_SCALAR_FIELD(skip_validation);
 
 	return true;
 }
@@ -2189,23 +2197,6 @@ _equalCommonTableExpr(CommonTableExpr *a, CommonTableExpr *b)
 	return true;
 }
 
-static bool
-_equalFkConstraint(FkConstraint *a, FkConstraint *b)
-{
-	COMPARE_STRING_FIELD(constr_name);
-	COMPARE_NODE_FIELD(pktable);
-	COMPARE_NODE_FIELD(fk_attrs);
-	COMPARE_NODE_FIELD(pk_attrs);
-	COMPARE_SCALAR_FIELD(fk_matchtype);
-	COMPARE_SCALAR_FIELD(fk_upd_action);
-	COMPARE_SCALAR_FIELD(fk_del_action);
-	COMPARE_SCALAR_FIELD(deferrable);
-	COMPARE_SCALAR_FIELD(initdeferred);
-	COMPARE_SCALAR_FIELD(skip_validation);
-
-	return true;
-}
-
 static bool
 _equalXmlSerialize(XmlSerialize *a, XmlSerialize *b)
 {
@@ -2859,9 +2850,6 @@ equal(void *a, void *b)
 		case T_CommonTableExpr:
 			retval = _equalCommonTableExpr(a, b);
 			break;
-		case T_FkConstraint:
-			retval = _equalFkConstraint(a, b);
-			break;
 		case T_PrivGrantee:
 			retval = _equalPrivGrantee(a, b);
 			break;

src/backend/nodes/nodeFuncs.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/nodeFuncs.c,v 1.41 2009/07/16 06:33:42 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/nodeFuncs.c,v 1.42 2009/07/30 02:45:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -903,6 +903,9 @@ exprLocation(Node *expr)
 		case T_TypeName:
 			loc = ((TypeName *) expr)->location;
 			break;
+		case T_Constraint:
+			loc = ((Constraint *) expr)->location;
+			break;
 		case T_XmlSerialize:
 			/* XMLSERIALIZE keyword should always be the first thing */
 			loc = ((XmlSerialize *) expr)->location;

src/backend/nodes/outfuncs.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.362 2009/07/29 20:56:19 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.363 2009/07/30 02:45:37 tgl Exp $
  *
  * NOTES
  *	  Every node type that can appear in stored rules' parsetrees *must*
@@ -2277,18 +2277,39 @@ _outConstraint(StringInfo str, Constraint *node)
 {
 	WRITE_NODE_TYPE("CONSTRAINT");
 
-	WRITE_STRING_FIELD(name);
+	WRITE_STRING_FIELD(conname);
+	WRITE_BOOL_FIELD(deferrable);
+	WRITE_BOOL_FIELD(initdeferred);
+	WRITE_LOCATION_FIELD(location);
 
 	appendStringInfo(str, " :contype ");
 	switch (node->contype)
 	{
+		case CONSTR_NULL:
+			appendStringInfo(str, "NULL");
+			break;
+
+		case CONSTR_NOTNULL:
+			appendStringInfo(str, "NOT_NULL");
+			break;
+
+		case CONSTR_DEFAULT:
+			appendStringInfo(str, "DEFAULT");
+			WRITE_NODE_FIELD(raw_expr);
+			WRITE_STRING_FIELD(cooked_expr);
+			break;
+
+		case CONSTR_CHECK:
+			appendStringInfo(str, "CHECK");
+			WRITE_NODE_FIELD(raw_expr);
+			WRITE_STRING_FIELD(cooked_expr);
+			break;
+
 		case CONSTR_PRIMARY:
 			appendStringInfo(str, "PRIMARY_KEY");
 			WRITE_NODE_FIELD(keys);
 			WRITE_NODE_FIELD(options);
 			WRITE_STRING_FIELD(indexspace);
-			WRITE_BOOL_FIELD(deferrable);
-			WRITE_BOOL_FIELD(initdeferred);
 			break;
 
 		case CONSTR_UNIQUE:
@@ -2296,47 +2317,40 @@ _outConstraint(StringInfo str, Constraint *node)
 			WRITE_NODE_FIELD(keys);
 			WRITE_NODE_FIELD(options);
 			WRITE_STRING_FIELD(indexspace);
-			WRITE_BOOL_FIELD(deferrable);
-			WRITE_BOOL_FIELD(initdeferred);
 			break;
 
-		case CONSTR_CHECK:
-			appendStringInfo(str, "CHECK");
-			WRITE_NODE_FIELD(raw_expr);
-			WRITE_STRING_FIELD(cooked_expr);
+		case CONSTR_FOREIGN:
+			appendStringInfo(str, "FOREIGN_KEY");
+			WRITE_NODE_FIELD(pktable);
+			WRITE_NODE_FIELD(fk_attrs);
+			WRITE_NODE_FIELD(pk_attrs);
+			WRITE_CHAR_FIELD(fk_matchtype);
+			WRITE_CHAR_FIELD(fk_upd_action);
+			WRITE_CHAR_FIELD(fk_del_action);
+			WRITE_BOOL_FIELD(skip_validation);
 			break;
 
-		case CONSTR_DEFAULT:
-			appendStringInfo(str, "DEFAULT");
-			WRITE_NODE_FIELD(raw_expr);
-			WRITE_STRING_FIELD(cooked_expr);
+		case CONSTR_ATTR_DEFERRABLE:
+			appendStringInfo(str, "ATTR_DEFERRABLE");
 			break;
 
-		case CONSTR_NOTNULL:
-			appendStringInfo(str, "NOT_NULL");
+		case CONSTR_ATTR_NOT_DEFERRABLE:
+			appendStringInfo(str, "ATTR_NOT_DEFERRABLE");
 			break;
 
-		default:
-			appendStringInfo(str, "<unrecognized_constraint>");
+		case CONSTR_ATTR_DEFERRED:
+			appendStringInfo(str, "ATTR_DEFERRED");
 			break;
-	}
-}
 
-static void
-_outFkConstraint(StringInfo str, FkConstraint *node)
-{
-	WRITE_NODE_TYPE("FKCONSTRAINT");
+		case CONSTR_ATTR_IMMEDIATE:
+			appendStringInfo(str, "ATTR_IMMEDIATE");
+			break;
 
-	WRITE_STRING_FIELD(constr_name);
-	WRITE_NODE_FIELD(pktable);
-	WRITE_NODE_FIELD(fk_attrs);
-	WRITE_NODE_FIELD(pk_attrs);
-	WRITE_CHAR_FIELD(fk_matchtype);
-	WRITE_CHAR_FIELD(fk_upd_action);
-	WRITE_CHAR_FIELD(fk_del_action);
-	WRITE_BOOL_FIELD(deferrable);
-	WRITE_BOOL_FIELD(initdeferred);
-	WRITE_BOOL_FIELD(skip_validation);
+		default:
+			appendStringInfo(str, "<unrecognized_constraint %d>",
+							 (int) node->contype);
+			break;
+	}
 }
 
 
@@ -2765,9 +2779,6 @@ _outNode(StringInfo str, void *obj)
 			case T_Constraint:
 				_outConstraint(str, obj);
 				break;
-			case T_FkConstraint:
-				_outFkConstraint(str, obj);
-				break;
 			case T_FuncCall:
 				_outFuncCall(str, obj);
 				break;

src/backend/parser/gram.y

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.674 2009/07/29 20:56:19 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.675 2009/07/30 02:45:37 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -2172,24 +2172,11 @@ ColQualList:
 ColConstraint:
 			CONSTRAINT name ColConstraintElem
 				{
-					switch (nodeTag($3))
-					{
-						case T_Constraint:
-							{
-								Constraint *n = (Constraint *)$3;
-								n->name = $2;
-							}
-							break;
-						case T_FkConstraint:
-							{
-								FkConstraint *n = (FkConstraint *)$3;
-								n->constr_name = $2;
-							}
-							break;
-						default:
-							break;
-					}
-					$$ = $3;
+					Constraint *n = (Constraint *) $3;
+					Assert(IsA(n, Constraint));
+					n->conname = $2;
+					n->location = @1;
+					$$ = (Node *) n;
 				}
 			| ColConstraintElem						{ $$ = $1; }
 			| ConstraintAttr						{ $$ = $1; }
@@ -2215,94 +2202,66 @@ ColConstraintElem:
 				{
 					Constraint *n = makeNode(Constraint);
 					n->contype = CONSTR_NOTNULL;
-					n->name = NULL;
-					n->raw_expr = NULL;
-					n->cooked_expr = NULL;
-					n->keys = NULL;
-					n->indexspace = NULL;
-					n->deferrable = FALSE;
-					n->initdeferred = FALSE;
+					n->location = @1;
 					$$ = (Node *)n;
 				}
 			| NULL_P
 				{
 					Constraint *n = makeNode(Constraint);
 					n->contype = CONSTR_NULL;
-					n->name = NULL;
-					n->raw_expr = NULL;
-					n->cooked_expr = NULL;
-					n->keys = NULL;
-					n->indexspace = NULL;
-					n->deferrable = FALSE;
-					n->initdeferred = FALSE;
+					n->location = @1;
 					$$ = (Node *)n;
 				}
 			| UNIQUE opt_definition OptConsTableSpace
 				{
 					Constraint *n = makeNode(Constraint);
 					n->contype = CONSTR_UNIQUE;
-					n->name = NULL;
-					n->raw_expr = NULL;
-					n->cooked_expr = NULL;
+					n->location = @1;
 					n->keys = NULL;
 					n->options = $2;
 					n->indexspace = $3;
-					n->deferrable = FALSE;
-					n->initdeferred = FALSE;
 					$$ = (Node *)n;
 				}
 			| PRIMARY KEY opt_definition OptConsTableSpace
 				{
 					Constraint *n = makeNode(Constraint);
 					n->contype = CONSTR_PRIMARY;
-					n->name = NULL;
-					n->raw_expr = NULL;
-					n->cooked_expr = NULL;
+					n->location = @1;
 					n->keys = NULL;
 					n->options = $3;
 					n->indexspace = $4;
-					n->deferrable = FALSE;
-					n->initdeferred = FALSE;
 					$$ = (Node *)n;
 				}
 			| CHECK '(' a_expr ')'
 				{
 					Constraint *n = makeNode(Constraint);
 					n->contype = CONSTR_CHECK;
-					n->name = NULL;
+					n->location = @1;
 					n->raw_expr = $3;
 					n->cooked_expr = NULL;
-					n->keys = NULL;
-					n->indexspace = NULL;
-					n->deferrable = FALSE;
-					n->initdeferred = FALSE;
 					$$ = (Node *)n;
 				}
 			| DEFAULT b_expr
 				{
 					Constraint *n = makeNode(Constraint);
 					n->contype = CONSTR_DEFAULT;
-					n->name = NULL;
+					n->location = @1;
 					n->raw_expr = $2;
 					n->cooked_expr = NULL;
-					n->keys = NULL;
-					n->indexspace = NULL;
-					n->deferrable = FALSE;
-					n->initdeferred = FALSE;
 					$$ = (Node *)n;
 				}
 			| REFERENCES qualified_name opt_column_list key_match key_actions
 				{
-					FkConstraint *n = makeNode(FkConstraint);
-					n->constr_name		= NULL;
+					Constraint *n = makeNode(Constraint);
+					n->contype = CONSTR_FOREIGN;
+					n->location = @1;
 					n->pktable			= $2;
 					n->fk_attrs			= NIL;
 					n->pk_attrs			= $3;
 					n->fk_matchtype		= $4;
 					n->fk_upd_action	= (char) ($5 >> 8);
 					n->fk_del_action	= (char) ($5 & 0xFF);
-					n->deferrable		= FALSE;
-					n->initdeferred		= FALSE;
+					n->skip_validation  = FALSE;
 					$$ = (Node *)n;
 				}
 		;
@@ -2324,24 +2283,28 @@ ConstraintAttr:
 				{
 					Constraint *n = makeNode(Constraint);
 					n->contype = CONSTR_ATTR_DEFERRABLE;
+					n->location = @1;
 					$$ = (Node *)n;
 				}
 			| NOT DEFERRABLE
 				{
 					Constraint *n = makeNode(Constraint);
 					n->contype = CONSTR_ATTR_NOT_DEFERRABLE;
+					n->location = @1;
 					$$ = (Node *)n;
 				}
 			| INITIALLY DEFERRED
 				{
 					Constraint *n = makeNode(Constraint);
 					n->contype = CONSTR_ATTR_DEFERRED;
+					n->location = @1;
 					$$ = (Node *)n;
 				}
 			| INITIALLY IMMEDIATE
 				{
 					Constraint *n = makeNode(Constraint);
 					n->contype = CONSTR_ATTR_IMMEDIATE;
+					n->location = @1;
 					$$ = (Node *)n;
 				}
 		;
@@ -2387,24 +2350,11 @@ TableLikeOption:
 TableConstraint:
 			CONSTRAINT name ConstraintElem
 				{
-					switch (nodeTag($3))
-					{
-						case T_Constraint:
-							{
-								Constraint *n = (Constraint *)$3;
-								n->name = $2;
-							}
-							break;
-						case T_FkConstraint:
-							{
-								FkConstraint *n = (FkConstraint *)$3;
-								n->constr_name = $2;
-							}
-							break;
-						default:
-							break;
-					}
-					$$ = $3;
+					Constraint *n = (Constraint *) $3;
+					Assert(IsA(n, Constraint));
+					n->conname = $2;
+					n->location = @1;
+					$$ = (Node *) n;
 				}
 			| ConstraintElem						{ $$ = $1; }
 		;
@@ -2414,17 +2364,14 @@ ConstraintElem:
 				{
 					Constraint *n = makeNode(Constraint);
 					n->contype = CONSTR_CHECK;
-					n->name = NULL;
+					n->location = @1;
 					n->raw_expr = $3;
 					n->cooked_expr = NULL;
-					n->indexspace = NULL;
 					if ($5 != 0)
 						ereport(ERROR,
 								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 								 errmsg("CHECK constraints cannot be deferred"),
 								 parser_errposition(@5)));
-					n->deferrable = FALSE;
-					n->initdeferred = FALSE;
 					$$ = (Node *)n;
 				}
 			| UNIQUE '(' columnList ')' opt_definition OptConsTableSpace
@@ -2432,9 +2379,7 @@ ConstraintElem:
 				{
 					Constraint *n = makeNode(Constraint);
 					n->contype = CONSTR_UNIQUE;
-					n->name = NULL;
-					n->raw_expr = NULL;
-					n->cooked_expr = NULL;
+					n->location = @1;
 					n->keys = $3;
 					n->options = $5;
 					n->indexspace = $6;
@@ -2447,9 +2392,7 @@ ConstraintElem:
 				{
 					Constraint *n = makeNode(Constraint);
 					n->contype = CONSTR_PRIMARY;
-					n->name = NULL;
-					n->raw_expr = NULL;
-					n->cooked_expr = NULL;
+					n->location = @1;
 					n->keys = $4;
 					n->options = $6;
 					n->indexspace = $7;
@@ -2460,14 +2403,16 @@ ConstraintElem:
 			| FOREIGN KEY '(' columnList ')' REFERENCES qualified_name
 				opt_column_list key_match key_actions ConstraintAttributeSpec
 				{
-					FkConstraint *n = makeNode(FkConstraint);
-					n->constr_name		= NULL;
+					Constraint *n = makeNode(Constraint);
+					n->contype = CONSTR_FOREIGN;
+					n->location = @1;
 					n->pktable			= $7;
 					n->fk_attrs			= $4;
 					n->pk_attrs			= $8;
 					n->fk_matchtype		= $9;
 					n->fk_upd_action	= (char) ($10 >> 8);
 					n->fk_del_action	= (char) ($10 & 0xFF);
+					n->skip_validation  = FALSE;
 					n->deferrable		= ($11 & 1) != 0;
 					n->initdeferred		= ($11 & 2) != 0;
 					$$ = (Node *)n;

src/include/nodes/nodes.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/nodes.h,v 1.223 2009/06/11 14:49:11 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/nodes.h,v 1.224 2009/07/30 02:45:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -364,7 +364,6 @@ typedef enum NodeTag
 	T_RangeTblEntry,
 	T_SortGroupClause,
 	T_WindowClause,
-	T_FkConstraint,
 	T_PrivGrantee,
 	T_FuncWithArgs,
 	T_AccessPriv,

src/include/nodes/parsenodes.h

@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.399 2009/07/29 20:56:21 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.400 2009/07/30 02:45:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1317,10 +1317,10 @@ typedef struct VariableShowStmt
 /* ----------------------
  *		Create Table Statement
  *
- * NOTE: in the raw gram.y output, ColumnDef, Constraint, and FkConstraint
- * nodes are intermixed in tableElts, and constraints is NIL.  After parse
- * analysis, tableElts contains just ColumnDefs, and constraints contains
- * just Constraint nodes (in fact, only CONSTR_CHECK nodes, in the present
+ * NOTE: in the raw gram.y output, ColumnDef and Constraint nodes are
+ * intermixed in tableElts, and constraints is NIL.  After parse analysis,
+ * tableElts contains just ColumnDefs, and constraints contains just
+ * Constraint nodes (in fact, only CONSTR_CHECK nodes, in the present
  * implementation).
  * ----------------------
  */
@@ -1339,23 +1339,32 @@ typedef struct CreateStmt
 } CreateStmt;
 
 /* ----------
- * Definitions for plain (non-FOREIGN KEY) constraints in CreateStmt
+ * Definitions for constraints in CreateStmt
  *
- * XXX probably these ought to be unified with FkConstraints at some point?
- * To this end we include CONSTR_FOREIGN in the ConstrType enum, even though
- * the parser does not generate it.
+ * Note that column defaults are treated as a type of constraint,
+ * even though that's a bit odd semantically.
  *
- * For constraints that use expressions (CONSTR_DEFAULT, CONSTR_CHECK)
+ * For constraints that use expressions (CONSTR_CHECK, CONSTR_DEFAULT)
  * we may have the expression in either "raw" form (an untransformed
  * parse tree) or "cooked" form (the nodeToString representation of
  * an executable expression tree), depending on how this Constraint
  * node was created (by parsing, or by inheritance from an existing
  * relation).  We should never have both in the same node!
  *
+ * FKCONSTR_ACTION_xxx values are stored into pg_constraint.confupdtype
+ * and pg_constraint.confdeltype columns; FKCONSTR_MATCH_xxx values are
+ * stored into pg_constraint.confmatchtype.  Changing the code values may
+ * require an initdb!
+ *
+ * If skip_validation is true then we skip checking that the existing rows
+ * in the table satisfy the constraint, and just install the catalog entries
+ * for the constraint.	This is currently used only during CREATE TABLE
+ * (when we know the table must be empty).
+ *
  * Constraint attributes (DEFERRABLE etc) are initially represented as
  * separate Constraint nodes for simplicity of parsing.  parse_utilcmd.c makes
- * a pass through the constraints list to attach the info to the appropriate
- * Constraint and FkConstraint nodes.
+ * a pass through the constraints list to insert the info into the appropriate
+ * Constraint node.
  * ----------
  */
 
@@ -1365,69 +1374,56 @@ typedef enum ConstrType			/* types of constraints */
 	CONSTR_NOTNULL,
 	CONSTR_DEFAULT,
 	CONSTR_CHECK,
-	CONSTR_FOREIGN,
 	CONSTR_PRIMARY,
 	CONSTR_UNIQUE,
+	CONSTR_FOREIGN,
 	CONSTR_ATTR_DEFERRABLE,		/* attributes for previous constraint node */
 	CONSTR_ATTR_NOT_DEFERRABLE,
 	CONSTR_ATTR_DEFERRED,
 	CONSTR_ATTR_IMMEDIATE
 } ConstrType;
 
-typedef struct Constraint
-{
-	NodeTag		type;
-	ConstrType	contype;
-	char	   *name;			/* name, or NULL if unnamed */
-	Node	   *raw_expr;		/* expr, as untransformed parse tree */
-	char	   *cooked_expr;	/* expr, as nodeToString representation */
-	List	   *keys;			/* String nodes naming referenced column(s) */
-	List	   *options;		/* options from WITH clause */
-	char	   *indexspace;		/* index tablespace for PKEY/UNIQUE
-								 * constraints; NULL for default */
-	bool		deferrable;		/* DEFERRABLE */
-	bool		initdeferred;	/* INITIALLY DEFERRED */
-} Constraint;
-
-/* ----------
- * Definitions for FOREIGN KEY constraints in CreateStmt
- *
- * Note: FKCONSTR_ACTION_xxx values are stored into pg_constraint.confupdtype
- * and pg_constraint.confdeltype columns; FKCONSTR_MATCH_xxx values are
- * stored into pg_constraint.confmatchtype.  Changing the code values may
- * require an initdb!
- *
- * If skip_validation is true then we skip checking that the existing rows
- * in the table satisfy the constraint, and just install the catalog entries
- * for the constraint.	This is currently used only during CREATE TABLE
- * (when we know the table must be empty).
- * ----------
- */
+/* Foreign key action codes */
 #define FKCONSTR_ACTION_NOACTION	'a'
 #define FKCONSTR_ACTION_RESTRICT	'r'
 #define FKCONSTR_ACTION_CASCADE		'c'
 #define FKCONSTR_ACTION_SETNULL		'n'
 #define FKCONSTR_ACTION_SETDEFAULT	'd'
 
+/* Foreign key matchtype codes */
 #define FKCONSTR_MATCH_FULL			'f'
 #define FKCONSTR_MATCH_PARTIAL		'p'
 #define FKCONSTR_MATCH_UNSPECIFIED	'u'
 
-typedef struct FkConstraint
+typedef struct Constraint
 {
 	NodeTag		type;
-	char	   *constr_name;	/* Constraint name, or NULL if unnamed */
+	ConstrType	contype;		/* see above */
+
+	/* Fields used for most/all constraint types: */
+	char	   *conname;		/* Constraint name, or NULL if unnamed */
+	bool		deferrable;		/* DEFERRABLE? */
+	bool		initdeferred;	/* INITIALLY DEFERRED? */
+	int			location;		/* token location, or -1 if unknown */
+
+	/* Fields used for constraints with expressions (CHECK and DEFAULT): */
+	Node	   *raw_expr;		/* expr, as untransformed parse tree */
+	char	   *cooked_expr;	/* expr, as nodeToString representation */
+
+	/* Fields used for index constraints (UNIQUE and PRIMARY KEY): */
+	List	   *keys;			/* String nodes naming referenced column(s) */
+	List	   *options;		/* options from WITH clause */
+	char	   *indexspace;		/* index tablespace; NULL for default */
+
+	/* Fields used for FOREIGN KEY constraints: */
 	RangeVar   *pktable;		/* Primary key table */
 	List	   *fk_attrs;		/* Attributes of foreign key */
 	List	   *pk_attrs;		/* Corresponding attrs in PK table */
 	char		fk_matchtype;	/* FULL, PARTIAL, UNSPECIFIED */
 	char		fk_upd_action;	/* ON UPDATE action */
 	char		fk_del_action;	/* ON DELETE action */
-	bool		deferrable;		/* DEFERRABLE */
-	bool		initdeferred;	/* INITIALLY DEFERRED */
 	bool		skip_validation;	/* skip validation of existing rows? */
-} FkConstraint;
-
+} Constraint;
 
 /* ----------------------
  *		Create/Drop Table Space Statements