get_object_address: separate domain constraints from table constraints

Apart from enabling comments on domain constraints, this enables a
future project to replicate object dropping to remote servers: with the
current mechanism there's no way to distinguish between the two types of
constraints, so there's no way to know what to drop.

Also added support for the domain constraint comments in psql's \dd and
pg_dump.

Catalog version bumped due to the change in ObjectType enum.

Author: alvherre

doc/src/sgml/ref/comment.sgml

@@ -28,6 +28,7 @@ COMMENT ON
   COLLATION <replaceable class="PARAMETER">object_name</replaceable> |
   COLUMN <replaceable class="PARAMETER">relation_name</replaceable>.<replaceable class="PARAMETER">column_name</replaceable> |
   CONSTRAINT <replaceable class="PARAMETER">constraint_name</replaceable> ON <replaceable class="PARAMETER">table_name</replaceable> |
+  CONSTRAINT <replaceable class="PARAMETER">constraint_name</replaceable> ON DOMAIN <replaceable class="PARAMETER">domain_name</replaceable> |
   CONVERSION <replaceable class="PARAMETER">object_name</replaceable> |
   DATABASE <replaceable class="PARAMETER">object_name</replaceable> |
   DOMAIN <replaceable class="PARAMETER">object_name</replaceable> |
@@ -126,6 +127,18 @@ COMMENT ON
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term><replaceable class="parameter">table_name</replaceable></term>
+    <term><replaceable class="parameter">domain_name</replaceable></term>
+    <listitem>
+     <para>
+      When creating a comment on a constraint on a table or a domain, these
+      parameteres specify the name of the table or domain on which the
+      constraint is defined.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
      <term><replaceable>source_type</replaceable></term>
      <listitem>
@@ -266,6 +279,7 @@ COMMENT ON COLLATION "fr_CA" IS 'Canadian French';
 COMMENT ON COLUMN my_table.my_column IS 'Employee ID number';
 COMMENT ON CONVERSION my_conv IS 'Conversion to UTF8';
 COMMENT ON CONSTRAINT bar_col_cons ON bar IS 'Constrains column col';
+COMMENT ON CONSTRAINT dom_col_constr ON DOMAIN dom IS 'Constrains col of domain';
 COMMENT ON DATABASE my_database IS 'Development Database';
 COMMENT ON DOMAIN my_domain IS 'Email Address Domain';
 COMMENT ON EXTENSION hstore IS 'implements the hstore data type';

src/backend/catalog/objectaddress.c

@@ -530,11 +530,28 @@ get_object_address(ObjectType objtype, List *objname, List *objargs,
 				break;
 			case OBJECT_RULE:
 			case OBJECT_TRIGGER:
-			case OBJECT_CONSTRAINT:
+			case OBJECT_TABCONSTRAINT:
 			case OBJECT_POLICY:
 				address = get_object_address_relobject(objtype, objname,
 													   &relation, missing_ok);
 				break;
+			case OBJECT_DOMCONSTRAINT:
+				{
+					List		   *domname;
+					ObjectAddress	domaddr;
+					char		   *constrname;
+
+					domname = list_truncate(list_copy(objname), list_length(objname) - 1);
+					constrname = strVal(llast(objname));
+					domaddr = get_object_address_type(OBJECT_DOMAIN, domname, missing_ok);
+
+					address.classId = ConstraintRelationId;
+					address.objectId = get_domain_constraint_oid(domaddr.objectId,
+															  constrname, missing_ok);
+					address.objectSubId = 0;
+
+				}
+				break;
 			case OBJECT_DATABASE:
 			case OBJECT_EXTENSION:
 			case OBJECT_TABLESPACE:
@@ -934,7 +951,7 @@ get_object_address_relobject(ObjectType objtype, List *objname,
 	const char *depname;
 
 	/* Extract name of dependent object. */
-	depname = strVal(lfirst(list_tail(objname)));
+	depname = strVal(llast(objname));
 
 	/* Separate relation name from dependent object name. */
 	nnames = list_length(objname);
@@ -990,7 +1007,7 @@ get_object_address_relobject(ObjectType objtype, List *objname,
 					get_trigger_oid(reloid, depname, missing_ok) : InvalidOid;
 				address.objectSubId = 0;
 				break;
-			case OBJECT_CONSTRAINT:
+			case OBJECT_TABCONSTRAINT:
 				address.classId = ConstraintRelationId;
 				address.objectId = relation ?
 					get_relation_constraint_oid(reloid, depname, missing_ok) :
@@ -1178,7 +1195,7 @@ check_object_ownership(Oid roleid, ObjectType objtype, ObjectAddress address,
 		case OBJECT_RULE:
 		case OBJECT_TRIGGER:
 		case OBJECT_POLICY:
-		case OBJECT_CONSTRAINT:
+		case OBJECT_TABCONSTRAINT:
 			if (!pg_class_ownercheck(RelationGetRelid(relation), roleid))
 				aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
 							   RelationGetRelationName(relation));
@@ -1191,6 +1208,7 @@ check_object_ownership(Oid roleid, ObjectType objtype, ObjectAddress address,
 		case OBJECT_TYPE:
 		case OBJECT_DOMAIN:
 		case OBJECT_ATTRIBUTE:
+		case OBJECT_DOMCONSTRAINT:
 			if (!pg_type_ownercheck(address.objectId, roleid))
 				aclcheck_error_type(ACLCHECK_NOT_OWNER, address.objectId);
 			break;

src/backend/commands/alter.c

@@ -305,7 +305,8 @@ ExecRenameStmt(RenameStmt *stmt)
 {
 	switch (stmt->renameType)
 	{
-		case OBJECT_CONSTRAINT:
+		case OBJECT_TABCONSTRAINT:
+		case OBJECT_DOMCONSTRAINT:
 			return RenameConstraint(stmt);
 
 		case OBJECT_DATABASE:

src/backend/commands/event_trigger.c

@@ -1053,10 +1053,10 @@ EventTriggerSupportsObjectType(ObjectType obtype)
 		case OBJECT_ATTRIBUTE:
 		case OBJECT_CAST:
 		case OBJECT_COLUMN:
-		case OBJECT_CONSTRAINT:
 		case OBJECT_COLLATION:
 		case OBJECT_CONVERSION:
 		case OBJECT_DOMAIN:
+		case OBJECT_DOMCONSTRAINT:
 		case OBJECT_EXTENSION:
 		case OBJECT_FDW:
 		case OBJECT_FOREIGN_SERVER:
@@ -1073,6 +1073,7 @@ EventTriggerSupportsObjectType(ObjectType obtype)
 		case OBJECT_RULE:
 		case OBJECT_SCHEMA:
 		case OBJECT_SEQUENCE:
+		case OBJECT_TABCONSTRAINT:
 		case OBJECT_TABLE:
 		case OBJECT_TRIGGER:
 		case OBJECT_TSCONFIGURATION:

src/backend/commands/tablecmds.c

@@ -2457,7 +2457,7 @@ RenameConstraint(RenameStmt *stmt)
 	Oid			relid = InvalidOid;
 	Oid			typid = InvalidOid;
 
-	if (stmt->relationType == OBJECT_DOMAIN)
+	if (stmt->renameType == OBJECT_DOMCONSTRAINT)
 	{
 		Relation	rel;
 		HeapTuple	tup;

src/backend/parser/gram.y

@@ -5572,6 +5572,7 @@ opt_restart_seqs:
  *				 CAST (<src type> AS <dst type>) |
  *				 COLUMN <relname>.<colname> |
  *				 CONSTRAINT <constraintname> ON <relname> |
+ *				 CONSTRAINT <constraintname> ON DOMAIN <domainname> |
  *				 FUNCTION <funcname> (arg1, arg2, ...) |
  *				 LARGE OBJECT <oid> |
  *				 OPERATOR <op> (leftoperand_typ, rightoperand_typ) |
@@ -5623,12 +5624,21 @@ CommentStmt:
 			| COMMENT ON CONSTRAINT name ON any_name IS comment_text
 				{
 					CommentStmt *n = makeNode(CommentStmt);
-					n->objtype = OBJECT_CONSTRAINT;
+					n->objtype = OBJECT_TABCONSTRAINT;
 					n->objname = lappend($6, makeString($4));
 					n->objargs = NIL;
 					n->comment = $8;
 					$$ = (Node *) n;
 				}
+			| COMMENT ON CONSTRAINT name ON DOMAIN_P any_name IS comment_text
+				{
+					CommentStmt *n = makeNode(CommentStmt);
+					n->objtype = OBJECT_DOMCONSTRAINT;
+					n->objname = lappend($7, makeString($4));
+					n->objargs = NIL;
+					n->comment = $9;
+					$$ = (Node *) n;
+				}
 			| COMMENT ON POLICY name ON any_name IS comment_text
 				{
 					CommentStmt *n = makeNode(CommentStmt);
@@ -7355,8 +7365,7 @@ RenameStmt: ALTER AGGREGATE func_name aggr_args RENAME TO name
 			| ALTER DOMAIN_P any_name RENAME CONSTRAINT name TO name
 				{
 					RenameStmt *n = makeNode(RenameStmt);
-					n->renameType = OBJECT_CONSTRAINT;
-					n->relationType = OBJECT_DOMAIN;
+					n->renameType = OBJECT_DOMCONSTRAINT;
 					n->object = $3;
 					n->subname = $6;
 					n->newname = $8;
@@ -7624,8 +7633,7 @@ RenameStmt: ALTER AGGREGATE func_name aggr_args RENAME TO name
 			| ALTER TABLE relation_expr RENAME CONSTRAINT name TO name
 				{
 					RenameStmt *n = makeNode(RenameStmt);
-					n->renameType = OBJECT_CONSTRAINT;
-					n->relationType = OBJECT_TABLE;
+					n->renameType = OBJECT_TABCONSTRAINT;
 					n->relation = $3;
 					n->subname = $6;
 					n->newname = $8;

src/backend/parser/parse_utilcmd.c

@@ -896,7 +896,7 @@ transformTableLikeClause(CreateStmtContext *cxt, TableLikeClause *table_like_cla
 			{
 				CommentStmt *stmt = makeNode(CommentStmt);
 
-				stmt->objtype = OBJECT_CONSTRAINT;
+				stmt->objtype = OBJECT_TABCONSTRAINT;
 				stmt->objname = list_make3(makeString(cxt->relation->schemaname),
 										   makeString(cxt->relation->relname),
 										   makeString(n->conname));

src/backend/tcop/utility.c

@@ -1589,16 +1589,14 @@ AlterObjectTypeCommandTag(ObjectType objtype)
 		case OBJECT_COLUMN:
 			tag = "ALTER TABLE";
 			break;
-		case OBJECT_CONSTRAINT:
-			tag = "ALTER TABLE";
-			break;
 		case OBJECT_CONVERSION:
 			tag = "ALTER CONVERSION";
 			break;
 		case OBJECT_DATABASE:
 			tag = "ALTER DATABASE";
 			break;
 		case OBJECT_DOMAIN:
+		case OBJECT_DOMCONSTRAINT:
 			tag = "ALTER DOMAIN";
 			break;
 		case OBJECT_EXTENSION:
@@ -1650,6 +1648,7 @@ AlterObjectTypeCommandTag(ObjectType objtype)
 			tag = "ALTER SEQUENCE";
 			break;
 		case OBJECT_TABLE:
+		case OBJECT_TABCONSTRAINT:
 			tag = "ALTER TABLE";
 			break;
 		case OBJECT_TABLESPACE:

src/bin/pg_dump/pg_dump.c

@@ -9261,6 +9261,23 @@ dumpDomain(Archive *fout, DumpOptions *dopt, TypeInfo *tyinfo)
 			tyinfo->dobj.namespace->dobj.name,
 			tyinfo->rolname, tyinfo->typacl);
 
+	/* Dump any per-constraint comments */
+	for (i = 0; i < tyinfo->nDomChecks; i++)
+	{
+		ConstraintInfo *domcheck = &(tyinfo->domChecks[i]);
+		PQExpBuffer	labelq = createPQExpBuffer();
+
+		appendPQExpBuffer(labelq, "CONSTRAINT %s ",
+						  fmtId(domcheck->dobj.name));
+		appendPQExpBuffer(labelq, "ON DOMAIN %s",
+						  fmtId(qtypname));
+		dumpComment(fout, dopt, labelq->data,
+					tyinfo->dobj.namespace->dobj.name,
+					tyinfo->rolname,
+					domcheck->dobj.catId, 0, tyinfo->dobj.dumpId);
+		destroyPQExpBuffer(labelq);
+	}
+
 	destroyPQExpBuffer(q);
 	destroyPQExpBuffer(delq);
 	destroyPQExpBuffer(labelq);

src/bin/psql/describe.c

@@ -952,7 +952,7 @@ objectDescription(const char *pattern, bool showSystem)
 					  gettext_noop("Object"),
 					  gettext_noop("Description"));
 
-	/* Constraint descriptions */
+	/* Table constraint descriptions */
 	appendPQExpBuffer(&buf,
 					  "  SELECT pgc.oid as oid, pgc.tableoid AS tableoid,\n"
 					  "  n.nspname as nspname,\n"
@@ -963,7 +963,7 @@ objectDescription(const char *pattern, bool showSystem)
 					  "ON c.oid = pgc.conrelid\n"
 					  "    LEFT JOIN pg_catalog.pg_namespace n "
 					  "    ON n.oid = c.relnamespace\n",
-					  gettext_noop("constraint"));
+					  gettext_noop("table constraint"));
 
 	if (!showSystem && !pattern)
 		appendPQExpBufferStr(&buf, "WHERE n.nspname <> 'pg_catalog'\n"
@@ -973,6 +973,29 @@ objectDescription(const char *pattern, bool showSystem)
 						  false, "n.nspname", "pgc.conname", NULL,
 						  "pg_catalog.pg_table_is_visible(c.oid)");
 
+	/* Domain constraint descriptions */
+	appendPQExpBuffer(&buf,
+					  "UNION ALL\n"
+					  "  SELECT pgc.oid as oid, pgc.tableoid AS tableoid,\n"
+					  "  n.nspname as nspname,\n"
+					  "  CAST(pgc.conname AS pg_catalog.text) as name,"
+					  "  CAST('%s' AS pg_catalog.text) as object\n"
+					  "  FROM pg_catalog.pg_constraint pgc\n"
+					  "    JOIN pg_catalog.pg_type t "
+					  "ON t.oid = pgc.contypid\n"
+					  "    LEFT JOIN pg_catalog.pg_namespace n "
+					  "    ON n.oid = t.typnamespace\n",
+					  gettext_noop("domain constraint"));
+
+	if (!showSystem && !pattern)
+		appendPQExpBufferStr(&buf, "WHERE n.nspname <> 'pg_catalog'\n"
+							 "      AND n.nspname <> 'information_schema'\n");
+
+	processSQLNamePattern(pset.db, &buf, pattern, !showSystem && !pattern,
+						  false, "n.nspname", "pgc.conname", NULL,
+						  "pg_catalog.pg_type_is_visible(t.oid)");
+
+
 	/*
 	 * pg_opclass.opcmethod only available in 8.3+
 	 */

src/include/nodes/parsenodes.h

@@ -1208,11 +1208,11 @@ typedef enum ObjectType
 	OBJECT_ATTRIBUTE,			/* type's attribute, when distinct from column */
 	OBJECT_CAST,
 	OBJECT_COLUMN,
-	OBJECT_CONSTRAINT,
 	OBJECT_COLLATION,
 	OBJECT_CONVERSION,
 	OBJECT_DATABASE,
 	OBJECT_DOMAIN,
+	OBJECT_DOMCONSTRAINT,
 	OBJECT_EVENT_TRIGGER,
 	OBJECT_EXTENSION,
 	OBJECT_FDW,
@@ -1231,6 +1231,7 @@ typedef enum ObjectType
 	OBJECT_RULE,
 	OBJECT_SCHEMA,
 	OBJECT_SEQUENCE,
+	OBJECT_TABCONSTRAINT,
 	OBJECT_TABLE,
 	OBJECT_TABLESPACE,
 	OBJECT_TRIGGER,

src/test/regress/input/constraints.source

@@ -478,3 +478,24 @@ UPDATE deferred_excl SET f1 = 3;
 ALTER TABLE deferred_excl ADD EXCLUDE (f1 WITH =);
 
 DROP TABLE deferred_excl;
+
+-- Comments
+CREATE TABLE constraint_comments_tbl (a int CONSTRAINT the_constraint CHECK (a > 0));
+CREATE DOMAIN constraint_comments_dom AS int CONSTRAINT the_constraint CHECK (value > 0);
+
+COMMENT ON CONSTRAINT the_constraint ON constraint_comments_tbl IS 'yes, the comment';
+COMMENT ON CONSTRAINT the_constraint ON DOMAIN constraint_comments_dom IS 'yes, another comment';
+
+-- no such constraint
+COMMENT ON CONSTRAINT no_constraint ON constraint_comments_tbl IS 'yes, the comment';
+COMMENT ON CONSTRAINT no_constraint ON DOMAIN constraint_comments_dom IS 'yes, another comment';
+
+-- no such table/domain
+COMMENT ON CONSTRAINT the_constraint ON no_comments_tbl IS 'bad comment';
+COMMENT ON CONSTRAINT the_constraint ON DOMAIN no_comments_dom IS 'another bad comment';
+
+COMMENT ON CONSTRAINT the_constraint ON constraint_comments_tbl IS NULL;
+COMMENT ON CONSTRAINT the_constraint ON DOMAIN constraint_comments_dom IS NULL;
+
+DROP TABLE constraint_comments_tbl;
+DROP DOMAIN constraint_comments_dom;

src/test/regress/output/constraints.source

@@ -645,3 +645,22 @@ ALTER TABLE deferred_excl ADD EXCLUDE (f1 WITH =);
 ERROR:  could not create exclusion constraint "deferred_excl_f1_excl"
 DETAIL:  Key (f1)=(3) conflicts with key (f1)=(3).
 DROP TABLE deferred_excl;
+-- Comments
+CREATE TABLE constraint_comments_tbl (a int CONSTRAINT the_constraint CHECK (a > 0));
+CREATE DOMAIN constraint_comments_dom AS int CONSTRAINT the_constraint CHECK (value > 0);
+COMMENT ON CONSTRAINT the_constraint ON constraint_comments_tbl IS 'yes, the comment';
+COMMENT ON CONSTRAINT the_constraint ON DOMAIN constraint_comments_dom IS 'yes, another comment';
+-- no such constraint
+COMMENT ON CONSTRAINT no_constraint ON constraint_comments_tbl IS 'yes, the comment';
+ERROR:  constraint "no_constraint" for table "constraint_comments_tbl" does not exist
+COMMENT ON CONSTRAINT no_constraint ON DOMAIN constraint_comments_dom IS 'yes, another comment';
+ERROR:  constraint "no_constraint" for domain "constraint_comments_dom" does not exist
+-- no such table/domain
+COMMENT ON CONSTRAINT the_constraint ON no_comments_tbl IS 'bad comment';
+ERROR:  relation "no_comments_tbl" does not exist
+COMMENT ON CONSTRAINT the_constraint ON DOMAIN no_comments_dom IS 'another bad comment';
+ERROR:  type "no_comments_dom" does not exist
+COMMENT ON CONSTRAINT the_constraint ON constraint_comments_tbl IS NULL;
+COMMENT ON CONSTRAINT the_constraint ON DOMAIN constraint_comments_dom IS NULL;
+DROP TABLE constraint_comments_tbl;
+DROP DOMAIN constraint_comments_dom;