Change the rules for inherited CHECK constraints to be essentially the same

as those for inherited columns; that is, it's no longer allowed for a child
table to not have a check constraint matching one that exists on a parent.
This satisfies the principle of least surprise (rows selected from the parent
will always appear to meet its check constraints) and eliminates some
longstanding bogosity in pg_dump, which formerly had to guess about whether
check constraints were really inherited or not.

The implementation involves adding conislocal and coninhcount columns to
pg_constraint (paralleling attislocal and attinhcount in pg_attribute)
and refactoring various ALTER TABLE actions to be more like those for
columns.

Alex Hunsaker, Nikhil Sontakke, Tom Lane

doc/src/sgml/catalogs.sgml

@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.165 2008/04/14 17:05:32 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.166 2008/05/09 23:32:03 tgl Exp $ -->
 <!--
  Documentation of the system catalogs, directed toward PostgreSQL developers
  -->
@@ -1907,6 +1907,26 @@
       <entry>Foreign key match type</entry>
      </row>
 
+     <row>
+      <entry><structfield>conislocal</structfield></entry>
+      <entry><type>bool</type></entry>
+      <entry></entry>
+      <entry>
+       This constraint is defined locally in the relation.  Note that a
+       constraint can be locally defined and inherited simultaneously
+      </entry>
+     </row>
+
+     <row>
+      <entry><structfield>coninhcount</structfield></entry>
+      <entry><type>int4</type></entry>
+      <entry></entry>
+      <entry>
+       The number of direct ancestors this constraint has.  A constraint with
+       a nonzero number of ancestors cannot be dropped nor renamed
+      </entry>
+     </row>
+
      <row>
       <entry><structfield>conkey</structfield></entry>
       <entry><type>int2[]</type></entry>

doc/src/sgml/ddl.sgml

@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/ddl.sgml,v 1.81 2008/01/13 17:58:54 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/ddl.sgml,v 1.82 2008/05/09 23:32:03 tgl Exp $ -->
 
 <chapter id="ddl">
  <title>Data Definition</title>
@@ -2107,7 +2107,8 @@ VALUES ('New York', NULL, NULL, 'NY');
 
   <para>
    A parent table cannot be dropped while any of its children remain. Neither
-   can columns of child tables be dropped or altered if they are inherited
+   can columns or check constraints of child tables be dropped or altered
+   if they are inherited
    from any parent tables. If you wish to remove a table and all of its
    descendants, one easy way is to drop the parent table with the
    <literal>CASCADE</literal> option.
@@ -2117,7 +2118,7 @@ VALUES ('New York', NULL, NULL, 'NY');
    <xref linkend="sql-altertable" endterm="sql-altertable-title"> will
    propagate any changes in column data definitions and check
    constraints down the inheritance hierarchy.  Again, dropping
-   columns or constraints on parent tables is only possible when using
+   columns that are depended on by other tables is only possible when using
    the <literal>CASCADE</literal> option. <command>ALTER
    TABLE</command> follows the same rules for duplicate column merging
    and rejection that apply during <command>CREATE TABLE</command>.

doc/src/sgml/ref/alter_table.sgml

@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/alter_table.sgml,v 1.98 2007/11/28 15:42:31 petere Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/alter_table.sgml,v 1.99 2008/05/09 23:32:03 tgl Exp $
 PostgreSQL documentation
 -->
 
@@ -713,7 +713,8 @@ ALTER TABLE table ALTER COLUMN anycol TYPE anytype;
     The <literal>TRIGGER</>, <literal>CLUSTER</>, <literal>OWNER</>,
     and <literal>TABLESPACE</> actions never recurse to descendant tables;
     that is, they always act as though <literal>ONLY</> were specified.
-    Adding a constraint can recurse only for <literal>CHECK</> constraints.
+    Adding a constraint can recurse only for <literal>CHECK</> constraints,
+    and is required to do so for such constraints.
    </para>
 
    <para>
@@ -804,7 +805,7 @@ ALTER TABLE distributors ALTER COLUMN street DROP NOT NULL;
   </para>
 
   <para> 
-   To add a check constraint to a table:
+   To add a check constraint to a table and all its children:
 <programlisting>
 ALTER TABLE distributors ADD CONSTRAINT zipchk CHECK (char_length(zipcode) = 5);
 </programlisting>
@@ -817,6 +818,14 @@ ALTER TABLE distributors DROP CONSTRAINT zipchk;
 </programlisting>
   </para>
 
+  <para> 
+   To remove a check constraint from a table only:
+<programlisting>
+ALTER TABLE ONLY distributors DROP CONSTRAINT zipchk;
+</programlisting>
+   (The check constraint remains in place for any child tables.)
+  </para>
+
   <para> 
    To add a foreign key constraint to a table:
 <programlisting>

doc/src/sgml/ref/create_table.sgml

@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/create_table.sgml,v 1.109 2007/07/17 05:02:00 neilc Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/create_table.sgml,v 1.110 2008/05/09 23:32:04 tgl Exp $
 PostgreSQL documentation
 -->
 
@@ -210,16 +210,25 @@ and <replaceable class="PARAMETER">table_constraint</replaceable> is:
       the new table.  If the column name list of the new table
       contains a column name that is also inherited, the data type must
       likewise match the inherited column(s), and the column
-      definitions are merged into one.  However, inherited and new
+      definitions are merged into one.  If the
-      column declarations of the same name need not specify identical
-      constraints: all constraints provided from any declaration are
-      merged together and all are applied to the new table.  If the
       new table explicitly specifies a default value for the column,
       this default overrides any defaults from inherited declarations
       of the column.  Otherwise, any parents that specify default
       values for the column must all specify the same default, or an
       error will be reported.
      </para>
+
+     <para>
+      <literal>CHECK</> constraints are merged in essentially the same way as
+      columns: if multiple parent tables and/or the new table definition
+      contain identically-named <literal>CHECK</> constraints, these
+      constraints must all have the same check expression, or an error will be
+      reported.  Constraints having the same name and expression will
+      be merged into one copy.  Notice that an unnamed <literal>CHECK</>
+      constraint in the new table will never be merged, since a unique name
+      will always be chosen for it.
+     </para>
+
 <!--
      <para>
       <productname>PostgreSQL</> automatically allows the

src/backend/access/common/tupdesc.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/common/tupdesc.c,v 1.122 2008/01/01 19:45:46 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/common/tupdesc.c,v 1.123 2008/05/09 23:32:04 tgl Exp $
  *
  * NOTES
  *	  some of the executor utility code such as "ExecTypeFromTL" should be
@@ -505,20 +505,18 @@ BuildDescForRelation(List *schema)
 	AttrNumber	attnum;
 	ListCell   *l;
 	TupleDesc	desc;
-	AttrDefault *attrdef = NULL;
+	bool		has_not_null;
-	TupleConstr *constr = (TupleConstr *) palloc0(sizeof(TupleConstr));
 	char	   *attname;
 	Oid			atttypid;
 	int32		atttypmod;
 	int			attdim;
-	int			ndef = 0;
 
 	/*
 	 * allocate a new tuple descriptor
 	 */
 	natts = list_length(schema);
 	desc = CreateTemplateTupleDesc(natts, false);
-	constr->has_not_null = false;
+	has_not_null = false;
 
 	attnum = 0;
 
@@ -547,52 +545,25 @@ BuildDescForRelation(List *schema)
 						   atttypid, atttypmod, attdim);
 
 		/* Fill in additional stuff not handled by TupleDescInitEntry */
-		if (entry->is_not_null)
-			constr->has_not_null = true;
 		desc->attrs[attnum - 1]->attnotnull = entry->is_not_null;
-
+		has_not_null |= entry->is_not_null;
-		/*
-		 * Note we copy only pre-cooked default expressions. Digestion of raw
-		 * ones is someone else's problem.
-		 */
-		if (entry->cooked_default != NULL)
-		{
-			if (attrdef == NULL)
-				attrdef = (AttrDefault *) palloc(natts * sizeof(AttrDefault));
-			attrdef[ndef].adnum = attnum;
-			attrdef[ndef].adbin = pstrdup(entry->cooked_default);
-			ndef++;
-			desc->attrs[attnum - 1]->atthasdef = true;
-		}
-
 		desc->attrs[attnum - 1]->attislocal = entry->is_local;
 		desc->attrs[attnum - 1]->attinhcount = entry->inhcount;
 	}
 
-	if (constr->has_not_null || ndef > 0)
+	if (has_not_null)
 	{
-		desc->constr = constr;
+		TupleConstr *constr = (TupleConstr *) palloc0(sizeof(TupleConstr));
 
-		if (ndef > 0)			/* DEFAULTs */
+		constr->has_not_null = true;
-		{
-			if (ndef < natts)
-				constr->defval = (AttrDefault *)
-					repalloc(attrdef, ndef * sizeof(AttrDefault));
-			else
-				constr->defval = attrdef;
-			constr->num_defval = ndef;
-		}
-		else
-		{
 		constr->defval = NULL;
 		constr->num_defval = 0;
-		}
 		constr->check = NULL;
 		constr->num_check = 0;
+		desc->constr = constr;
 	}
 	else
 	{
-		pfree(constr);
 		desc->constr = NULL;
 	}
 

src/backend/bootstrap/bootparse.y

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/bootstrap/bootparse.y,v 1.91 2008/01/01 19:45:48 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/bootstrap/bootparse.y,v 1.92 2008/05/09 23:32:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -206,6 +206,7 @@ Boot_CreateStmt:
 													  $6,
 													  BOOTSTRAP_SUPERUSERID,
 													  tupdesc,
+													  NIL,
 													  RELKIND_RELATION,
 													  $3,
 													  true,

src/backend/catalog/heap.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/heap.c,v 1.332 2008/03/27 03:57:33 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/heap.c,v 1.333 2008/05/09 23:32:04 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -77,9 +77,15 @@ static Oid AddNewRelationType(const char *typeName,
 				   char new_rel_kind,
 				   Oid new_array_type);
 static void RelationRemoveInheritance(Oid relid);
-static void StoreRelCheck(Relation rel, char *ccname, char *ccbin);
+static void StoreRelCheck(Relation rel, char *ccname, Node *expr,
-static void StoreConstraints(Relation rel, TupleDesc tupdesc);
+						  bool is_local, int inhcount);
+static void StoreConstraints(Relation rel, List *cooked_constraints);
+static bool MergeWithExistingConstraint(Relation rel, char *ccname, Node *expr,
+										bool allow_merge, bool is_local);
 static void SetRelationNumChecks(Relation rel, int numchecks);
+static Node *cookConstraint(ParseState *pstate,
+			   Node *raw_constraint,
+			   char *relname);
 static List *insert_ordered_unique_oid(List *list, Oid datum);
 
 
@@ -788,6 +794,7 @@ heap_create_with_catalog(const char *relname,
 						 Oid relid,
 						 Oid ownerid,
 						 TupleDesc tupdesc,
+						 List *cooked_constraints,
 						 char relkind,
 						 bool shared_relation,
 						 bool oidislocal,
@@ -1004,13 +1011,13 @@ heap_create_with_catalog(const char *relname,
 	}
 
 	/*
-	 * store constraints and defaults passed in the tupdesc, if any.
+	 * Store any supplied constraints and defaults.
 	 *
 	 * NB: this may do a CommandCounterIncrement and rebuild the relcache
 	 * entry, so the relation must be valid and self-consistent at this point.
 	 * In particular, there are not yet constraints and defaults anywhere.
 	 */
-	StoreConstraints(new_rel_desc, tupdesc);
+	StoreConstraints(new_rel_desc, cooked_constraints);
 
 	/*
 	 * If there's a special on-commit action, remember it
@@ -1426,12 +1433,11 @@ heap_drop_with_catalog(Oid relid)
 
 /*
  * Store a default expression for column attnum of relation rel.
- * The expression must be presented as a nodeToString() string.
  */
 void
-StoreAttrDefault(Relation rel, AttrNumber attnum, char *adbin)
+StoreAttrDefault(Relation rel, AttrNumber attnum, Node *expr)
 {
-	Node	   *expr;
+	char	   *adbin;
 	char	   *adsrc;
 	Relation	adrel;
 	HeapTuple	tuple;
@@ -1445,12 +1451,12 @@ StoreAttrDefault(Relation rel, AttrNumber attnum, char *adbin)
 				defobject;
 
 	/*
-	 * Need to construct source equivalent of given node-string.
+	 * Flatten expression to string form for storage.
 	 */
-	expr = stringToNode(adbin);
+	adbin = nodeToString(expr);
 
 	/*
-	 * deparse it
+	 * Also deparse it to form the mostly-obsolete adsrc field.
 	 */
 	adsrc = deparse_expression(expr,
 							deparse_context_for(RelationGetRelationName(rel),
@@ -1482,6 +1488,7 @@ StoreAttrDefault(Relation rel, AttrNumber attnum, char *adbin)
 	pfree(DatumGetPointer(values[Anum_pg_attrdef_adbin - 1]));
 	pfree(DatumGetPointer(values[Anum_pg_attrdef_adsrc - 1]));
 	heap_freetuple(tuple);
+	pfree(adbin);
 	pfree(adsrc);
 
 	/*
@@ -1525,27 +1532,27 @@ StoreAttrDefault(Relation rel, AttrNumber attnum, char *adbin)
 
 /*
  * Store a check-constraint expression for the given relation.
- * The expression must be presented as a nodeToString() string.
  *
  * Caller is responsible for updating the count of constraints
  * in the pg_class entry for the relation.
  */
 static void
-StoreRelCheck(Relation rel, char *ccname, char *ccbin)
+StoreRelCheck(Relation rel, char *ccname, Node *expr,
+			  bool is_local, int inhcount)
 {
-	Node	   *expr;
+	char	   *ccbin;
 	char	   *ccsrc;
 	List	   *varList;
 	int			keycount;
 	int16	   *attNos;
 
 	/*
-	 * Convert condition to an expression tree.
+	 * Flatten expression to string form for storage.
 	 */
-	expr = stringToNode(ccbin);
+	ccbin = nodeToString(expr);
 
 	/*
-	 * deparse it
+	 * Also deparse it to form the mostly-obsolete consrc field.
 	 */
 	ccsrc = deparse_expression(expr,
 							deparse_context_for(RelationGetRelationName(rel),
@@ -1553,7 +1560,7 @@ StoreRelCheck(Relation rel, char *ccname, char *ccbin)
 							   false, false);
 
 	/*
-	 * Find columns of rel that are used in ccbin
+	 * Find columns of rel that are used in expr
 	 *
 	 * NB: pull_var_clause is okay here only because we don't allow subselects
 	 * in check constraints; it would fail to examine the contents of
@@ -1608,26 +1615,29 @@ StoreRelCheck(Relation rel, char *ccname, char *ccbin)
 						  InvalidOid,	/* no associated index */
 						  expr, /* Tree form check constraint */
 						  ccbin,	/* Binary form check constraint */
-						  ccsrc);		/* Source form check constraint */
+						  ccsrc,	/* Source form check constraint */
+						  is_local,	/* conislocal */
+						  inhcount); /* coninhcount */
 
+	pfree(ccbin);
 	pfree(ccsrc);
 }
 
 /*
- * Store defaults and constraints passed in via the tuple constraint struct.
+ * Store defaults and constraints (passed as a list of CookedConstraint).
  *
  * NOTE: only pre-cooked expressions will be passed this way, which is to
  * say expressions inherited from an existing relation.  Newly parsed
  * expressions can be added later, by direct calls to StoreAttrDefault
- * and StoreRelCheck (see AddRelationRawConstraints()).
+ * and StoreRelCheck (see AddRelationNewConstraints()).
  */
 static void
-StoreConstraints(Relation rel, TupleDesc tupdesc)
+StoreConstraints(Relation rel, List *cooked_constraints)
 {
-	TupleConstr *constr = tupdesc->constr;
+	int			numchecks = 0;
-	int			i;
+	ListCell   *lc;
 
-	if (!constr)
+	if (!cooked_constraints)
 		return;					/* nothing to do */
 
 	/*
@@ -1637,33 +1647,46 @@ StoreConstraints(Relation rel, TupleDesc tupdesc)
 	 */
 	CommandCounterIncrement();
 
-	for (i = 0; i < constr->num_defval; i++)
+	foreach(lc, cooked_constraints)
-		StoreAttrDefault(rel, constr->defval[i].adnum,
+	{
-						 constr->defval[i].adbin);
+		CookedConstraint *con = (CookedConstraint *) lfirst(lc);
 
-	for (i = 0; i < constr->num_check; i++)
+		switch (con->contype)
-		StoreRelCheck(rel, constr->check[i].ccname,
+		{
-					  constr->check[i].ccbin);
+			case CONSTR_DEFAULT:
+				StoreAttrDefault(rel, con->attnum, con->expr);
+				break;
+			case CONSTR_CHECK:
+				StoreRelCheck(rel, con->name, con->expr,
+							  con->is_local, con->inhcount);
+				numchecks++;
+				break;
+			default:
+				elog(ERROR, "unrecognized constraint type: %d",
+					 (int) con->contype);
+		}
+	}
 
-	if (constr->num_check > 0)
+	if (numchecks > 0)
-		SetRelationNumChecks(rel, constr->num_check);
+		SetRelationNumChecks(rel, numchecks);
 }
 
 /*
- * AddRelationRawConstraints
+ * AddRelationNewConstraints
  *
- * Add raw (not-yet-transformed) column default expressions and/or constraint
+ * Add new column default expressions and/or constraint check expressions
- * check expressions to an existing relation.  This is defined to do both
+ * to an existing relation.  This is defined to do both for efficiency in
- * for efficiency in DefineRelation, but of course you can do just one or
+ * DefineRelation, but of course you can do just one or the other by passing
- * the other by passing empty lists.
+ * empty lists.
  *
  * rel: relation to be modified
- * rawColDefaults: list of RawColumnDefault structures
+ * newColDefaults: list of RawColumnDefault structures
- * rawConstraints: list of Constraint nodes
+ * newConstraints: list of Constraint nodes
+ * allow_merge: TRUE if check constraints may be merged with existing ones
+ * is_local: TRUE if definition is local, FALSE if it's inherited
  *
- * All entries in rawColDefaults will be processed.  Entries in rawConstraints
+ * All entries in newColDefaults will be processed.  Entries in newConstraints
- * will be processed only if they are CONSTR_CHECK type and contain a "raw"
+ * will be processed only if they are CONSTR_CHECK type.
- * expression.
  *
  * Returns a list of CookedConstraint nodes that shows the cooked form of
  * the default and constraint expressions added to the relation.
@@ -1674,9 +1697,11 @@ StoreConstraints(Relation rel, TupleDesc tupdesc)
  * tuples visible.
  */
 List *
-AddRelationRawConstraints(Relation rel,
+AddRelationNewConstraints(Relation rel,
-						  List *rawColDefaults,
+						  List *newColDefaults,
-						  List *rawConstraints)
+						  List *newConstraints,
+						  bool allow_merge,
+						  bool is_local)
 {
 	List	   *cookedConstraints = NIL;
 	TupleDesc	tupleDesc;
@@ -1715,7 +1740,7 @@ AddRelationRawConstraints(Relation rel,
 	/*
 	 * Process column default expressions.
 	 */
-	foreach(cell, rawColDefaults)
+	foreach(cell, newColDefaults)
 	{
 		RawColumnDefault *colDef = (RawColumnDefault *) lfirst(cell);
 		Form_pg_attribute atp = rel->rd_att->attrs[colDef->attnum - 1];
@@ -1739,13 +1764,15 @@ AddRelationRawConstraints(Relation rel,
 			(IsA(expr, Const) &&((Const *) expr)->constisnull))
 			continue;
 
-		StoreAttrDefault(rel, colDef->attnum, nodeToString(expr));
+		StoreAttrDefault(rel, colDef->attnum, expr);
 
 		cooked = (CookedConstraint *) palloc(sizeof(CookedConstraint));
 		cooked->contype = CONSTR_DEFAULT;
 		cooked->name = NULL;
 		cooked->attnum = colDef->attnum;
 		cooked->expr = expr;
+		cooked->is_local = is_local;
+		cooked->inhcount = is_local ? 0 : 1;
 		cookedConstraints = lappend(cookedConstraints, cooked);
 	}
 
@@ -1754,45 +1781,35 @@ AddRelationRawConstraints(Relation rel,
 	 */
 	numchecks = numoldchecks;
 	checknames = NIL;
-	foreach(cell, rawConstraints)
+	foreach(cell, newConstraints)
 	{
 		Constraint *cdef = (Constraint *) lfirst(cell);
 		char	   *ccname;
 
-		if (cdef->contype != CONSTR_CHECK || cdef->raw_expr == NULL)
+		if (cdef->contype != CONSTR_CHECK)
 			continue;
-		Assert(cdef->cooked_expr == NULL);
-
-		/*
-		 * Transform raw parsetree to executable expression.
-		 */
-		expr = transformExpr(pstate, cdef->raw_expr);
 
-		/*
+		if (cdef->raw_expr != NULL)
-		 * Make sure it yields a boolean result.
+		{
-		 */
+			Assert(cdef->cooked_expr == NULL);
-		expr = coerce_to_boolean(pstate, expr, "CHECK");
 
 			/*
-		 * Make sure no outside relations are referred to.
+			 * Transform raw parsetree to executable expression, and verify
+			 * it's valid as a CHECK constraint.
 			 */
-		if (list_length(pstate->p_rtable) != 1)
+			expr = cookConstraint(pstate, cdef->raw_expr,
-			ereport(ERROR,
+								  RelationGetRelationName(rel));
-					(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+		}
-			errmsg("only table \"%s\" can be referenced in check constraint",
+		else
-				   RelationGetRelationName(rel))));
+		{
+			Assert(cdef->cooked_expr != NULL);
 
 			/*
-		 * No subplans or aggregates, either...
+			 * Here, we assume the parser will only pass us valid CHECK
+			 * expressions, so we do no particular checking.
 			 */
-		if (pstate->p_hasSubLinks)
+			expr = stringToNode(cdef->cooked_expr);
-			ereport(ERROR,
+		}
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("cannot use subquery in check constraint")));
-		if (pstate->p_hasAggs)
-			ereport(ERROR,
-					(errcode(ERRCODE_GROUPING_ERROR),
-			   errmsg("cannot use aggregate function in check constraint")));
 
 		/*
 		 * Check name uniqueness, or generate a name if none was given.
@@ -1802,15 +1819,6 @@ AddRelationRawConstraints(Relation rel,
 			ListCell   *cell2;
 
 			ccname = cdef->name;
-			/* Check against pre-existing constraints */
-			if (ConstraintNameIsUsed(CONSTRAINT_RELATION,
-									 RelationGetRelid(rel),
-									 RelationGetNamespace(rel),
-									 ccname))
-				ereport(ERROR,
-						(errcode(ERRCODE_DUPLICATE_OBJECT),
-				errmsg("constraint \"%s\" for relation \"%s\" already exists",
-					   ccname, RelationGetRelationName(rel))));
 			/* Check against other new constraints */
 			/* Needed because we don't do CommandCounterIncrement in loop */
 			foreach(cell2, checknames)
@@ -1821,6 +1829,19 @@ AddRelationRawConstraints(Relation rel,
 							 errmsg("check constraint \"%s\" already exists",
 									ccname)));
 			}
+
+			/* save name for future checks */
+			checknames = lappend(checknames, ccname);
+
+			/*
+			 * Check against pre-existing constraints.  If we are allowed
+			 * to merge with an existing constraint, there's no more to
+			 * do here.  (We omit the duplicate constraint from the result,
+			 * which is what ATAddCheckConstraint wants.)
+			 */
+			if (MergeWithExistingConstraint(rel, ccname, expr,
+											allow_merge, is_local))
+				continue;
 		}
 		else
 		{
@@ -1855,15 +1876,15 @@ AddRelationRawConstraints(Relation rel,
 										  "check",
 										  RelationGetNamespace(rel),
 										  checknames);
-		}
 
 			/* save name for future checks */
 			checknames = lappend(checknames, ccname);
+		}
 
 		/*
 		 * OK, store it.
 		 */
-		StoreRelCheck(rel, ccname, nodeToString(expr));
+		StoreRelCheck(rel, ccname, expr, is_local, is_local ? 0 : 1);
 
 		numchecks++;
 
@@ -1872,6 +1893,8 @@ AddRelationRawConstraints(Relation rel,
 		cooked->name = ccname;
 		cooked->attnum = 0;
 		cooked->expr = expr;
+		cooked->is_local = is_local;
+		cooked->inhcount = is_local ? 0 : 1;
 		cookedConstraints = lappend(cookedConstraints, cooked);
 	}
 
@@ -1887,6 +1910,90 @@ AddRelationRawConstraints(Relation rel,
 	return cookedConstraints;
 }
 
+/*
+ * Check for a pre-existing check constraint that conflicts with a proposed
+ * new one, and either adjust its conislocal/coninhcount settings or throw
+ * error as needed.
+ *
+ * Returns TRUE if merged (constraint is a duplicate), or FALSE if it's
+ * got a so-far-unique name, or throws error if conflict.
+ */
+static bool
+MergeWithExistingConstraint(Relation rel, char *ccname, Node *expr,
+							bool allow_merge, bool is_local)
+{
+	bool		found;
+	Relation	conDesc;
+	SysScanDesc conscan;
+	ScanKeyData skey[2];
+	HeapTuple	tup;
+
+	/* Search for a pg_constraint entry with same name and relation */
+	conDesc = heap_open(ConstraintRelationId, RowExclusiveLock);
+
+	found = false;
+
+	ScanKeyInit(&skey[0],
+				Anum_pg_constraint_conname,
+				BTEqualStrategyNumber, F_NAMEEQ,
+				CStringGetDatum(ccname));
+
+	ScanKeyInit(&skey[1],
+				Anum_pg_constraint_connamespace,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(RelationGetNamespace(rel)));
+
+	conscan = systable_beginscan(conDesc, ConstraintNameNspIndexId, true,
+								 SnapshotNow, 2, skey);
+
+	while (HeapTupleIsValid(tup = systable_getnext(conscan)))
+	{
+		Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(tup);
+
+		if (con->conrelid == RelationGetRelid(rel))
+		{
+			/* Found it.  Conflicts if not identical check constraint */
+			if (con->contype == CONSTRAINT_CHECK)
+			{
+				Datum	val;
+				bool	isnull;
+
+				val = fastgetattr(tup,
+								  Anum_pg_constraint_conbin,
+								  conDesc->rd_att, &isnull);
+				if (isnull)
+					elog(ERROR, "null conbin for rel %s",
+						 RelationGetRelationName(rel));
+				if (equal(expr, stringToNode(TextDatumGetCString(val))))
+					found = true;
+			}
+			if (!found || !allow_merge)
+				ereport(ERROR,
+						(errcode(ERRCODE_DUPLICATE_OBJECT),
+				errmsg("constraint \"%s\" for relation \"%s\" already exists",
+					   ccname, RelationGetRelationName(rel))));
+			/* OK to update the tuple */
+			ereport(NOTICE,
+					(errmsg("merging constraint \"%s\" with inherited definition",
+							ccname)));
+			tup = heap_copytuple(tup);
+			con = (Form_pg_constraint) GETSTRUCT(tup);
+			if (is_local)
+				con->conislocal = true;
+			else
+				con->coninhcount++;
+			simple_heap_update(conDesc, &tup->t_self, tup);
+			CatalogUpdateIndexes(conDesc, tup);
+			break;
+		}
+	}
+
+	systable_endscan(conscan);
+	heap_close(conDesc, RowExclusiveLock);
+
+	return found;
+}
+
 /*
  * Update the count of constraints in the relation's pg_class tuple.
  *
@@ -2015,63 +2122,52 @@ cookDefault(ParseState *pstate,
 	return expr;
 }
 
-
 /*
- * Removes all constraints on a relation that match the given name.
+ * Take a raw CHECK constraint expression and convert it to a cooked format
+ * ready for storage.
  *
- * It is the responsibility of the calling function to acquire a suitable
+ * Parse state must be set up to recognize any vars that might appear
- * lock on the relation.
+ * in the expression.
- *
- * Returns: The number of constraints removed.
  */
-int
+static Node *
-RemoveRelConstraints(Relation rel, const char *constrName,
+cookConstraint(ParseState *pstate,
-					 DropBehavior behavior)
+			   Node *raw_constraint,
+			   char *relname)
 {
-	int			ndeleted = 0;
+	Node	   *expr;
-	Relation	conrel;
-	SysScanDesc conscan;
-	ScanKeyData key[1];
-	HeapTuple	contup;
-
-	/* Grab an appropriate lock on the pg_constraint relation */
-	conrel = heap_open(ConstraintRelationId, RowExclusiveLock);
-
-	/* Use the index to scan only constraints of the target relation */
-	ScanKeyInit(&key[0],
-				Anum_pg_constraint_conrelid,
-				BTEqualStrategyNumber, F_OIDEQ,
-				ObjectIdGetDatum(RelationGetRelid(rel)));
-
-	conscan = systable_beginscan(conrel, ConstraintRelidIndexId, true,
-								 SnapshotNow, 1, key);
 
 	/*
-	 * Scan over the result set, removing any matching entries.
+	 * Transform raw parsetree to executable expression.
 	 */
-	while ((contup = systable_getnext(conscan)) != NULL)
+	expr = transformExpr(pstate, raw_constraint);
-	{
-		Form_pg_constraint con = (Form_pg_constraint) GETSTRUCT(contup);
-
-		if (strcmp(NameStr(con->conname), constrName) == 0)
-		{
-			ObjectAddress conobj;
 
-			conobj.classId = ConstraintRelationId;
+	/*
-			conobj.objectId = HeapTupleGetOid(contup);
+	 * Make sure it yields a boolean result.
-			conobj.objectSubId = 0;
+	 */
-
+	expr = coerce_to_boolean(pstate, expr, "CHECK");
-			performDeletion(&conobj, behavior);
 
-			ndeleted++;
+	/*
-		}
+	 * Make sure no outside relations are referred to.
-	}
+	 */
+	if (list_length(pstate->p_rtable) != 1)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
+				 errmsg("only table \"%s\" can be referenced in check constraint",
+						relname)));
 
-	/* Clean up after the scan */
+	/*
-	systable_endscan(conscan);
+	 * No subplans or aggregates, either...
-	heap_close(conrel, RowExclusiveLock);
+	 */
+	if (pstate->p_hasSubLinks)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot use subquery in check constraint")));
+	if (pstate->p_hasAggs)
+		ereport(ERROR,
+				(errcode(ERRCODE_GROUPING_ERROR),
+				 errmsg("cannot use aggregate function in check constraint")));
 
-	return ndeleted;
+	return expr;
 }
 
 

src/backend/catalog/index.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.296 2008/03/26 21:10:37 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/index.c,v 1.297 2008/05/09 23:32:04 tgl Exp $
  *
  *
  * INTERFACE ROUTINES
@@ -716,7 +716,9 @@ index_create(Oid heapRelationId,
 										   InvalidOid,	/* no associated index */
 										   NULL,		/* no check constraint */
 										   NULL,
-										   NULL);
+										   NULL,
+										   true, /* islocal */
+										   0); /* inhcount */
 
 			referenced.classId = ConstraintRelationId;
 			referenced.objectId = conOid;

src/backend/catalog/pg_constraint.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/pg_constraint.c,v 1.40 2008/03/26 21:10:37 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/pg_constraint.c,v 1.41 2008/05/09 23:32:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -60,7 +60,9 @@ CreateConstraintEntry(const char *constraintName,
 					  Oid indexRelId,
 					  Node *conExpr,
 					  const char *conBin,
-					  const char *conSrc)
+					  const char *conSrc,
+					  bool conIsLocal,
+					  int conInhCount)
 {
 	Relation	conDesc;
 	Oid			conOid;
@@ -145,6 +147,8 @@ CreateConstraintEntry(const char *constraintName,
 	values[Anum_pg_constraint_confupdtype - 1] = CharGetDatum(foreignUpdateType);
 	values[Anum_pg_constraint_confdeltype - 1] = CharGetDatum(foreignDeleteType);
 	values[Anum_pg_constraint_confmatchtype - 1] = CharGetDatum(foreignMatchType);
+	values[Anum_pg_constraint_conislocal - 1] = BoolGetDatum(conIsLocal);
+	values[Anum_pg_constraint_coninhcount - 1] = Int32GetDatum(conInhCount);
 
 	if (conkeyArray)
 		values[Anum_pg_constraint_conkey - 1] = PointerGetDatum(conkeyArray);

src/backend/catalog/toasting.c

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/toasting.c,v 1.9 2008/01/01 19:45:48 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/toasting.c,v 1.10 2008/05/09 23:32:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -193,6 +193,7 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid)
 										   toastOid,
 										   rel->rd_rel->relowner,
 										   tupdesc,
+										   NIL,
 										   RELKIND_TOASTVALUE,
 										   shared_relation,
 										   true,

src/backend/commands/cluster.c

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/cluster.c,v 1.173 2008/04/13 19:18:14 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/cluster.c,v 1.174 2008/05/09 23:32:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -639,9 +639,12 @@ make_new_heap(Oid OIDOldHeap, const char *NewName, Oid NewTableSpace)
 
 	/*
 	 * Need to make a copy of the tuple descriptor, since
-	 * heap_create_with_catalog modifies it.
+	 * heap_create_with_catalog modifies it.  Note that the NewHeap will
+	 * not receive any of the defaults or constraints associated with the
+	 * OldHeap; we don't need 'em, and there's no reason to spend cycles
+	 * inserting them into the catalogs only to delete them.
 	 */
-	tupdesc = CreateTupleDescCopyConstr(OldHeapDesc);
+	tupdesc = CreateTupleDescCopy(OldHeapDesc);
 
 	/*
 	 * Use options of the old heap for new heap.
@@ -662,6 +665,7 @@ make_new_heap(Oid OIDOldHeap, const char *NewName, Oid NewTableSpace)
 										  InvalidOid,
 										  OldHeap->rd_rel->relowner,
 										  tupdesc,
+										  NIL,
 										  OldHeap->rd_rel->relkind,
 										  OldHeap->rd_rel->relisshared,
 										  true,

src/backend/commands/typecmds.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/typecmds.c,v 1.117 2008/03/27 03:57:33 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/typecmds.c,v 1.118 2008/05/09 23:32:04 tgl Exp $
  *
  * DESCRIPTION
  *	  The "DefineFoo" routines take the parse tree and pick out the
@@ -2206,7 +2206,9 @@ domainAddConstraint(Oid domainOid, Oid domainNamespace, Oid baseTypeOid,
 						  InvalidOid,
 						  expr, /* Tree form check constraint */
 						  ccbin,	/* Binary form check constraint */
-						  ccsrc);		/* Source form check constraint */
+						  ccsrc,	/* Source form check constraint */
+						  true, /* is local */
+						  0);	/* inhcount */
 
 	/*
 	 * Return the compiled constraint expression so the calling routine can

src/backend/executor/execMain.c

@@ -26,7 +26,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.306 2008/04/21 03:49:45 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.307 2008/05/09 23:32:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2626,7 +2626,7 @@ OpenIntoRel(QueryDesc *queryDesc)
 									 false);
 	(void) heap_reloptions(RELKIND_RELATION, reloptions, true);
 
-	/* have to copy the actual tupdesc to get rid of any constraints */
+	/* Copy the tupdesc because heap_create_with_catalog modifies it */
 	tupdesc = CreateTupleDescCopy(queryDesc->tupDesc);
 
 	/* Now we can actually create the new relation */
@@ -2636,6 +2636,7 @@ OpenIntoRel(QueryDesc *queryDesc)
 											  InvalidOid,
 											  GetUserId(),
 											  tupdesc,
+											  NIL,
 											  RELKIND_RELATION,
 											  false,
 											  true,

src/bin/pg_dump/common.c

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/bin/pg_dump/common.c,v 1.103 2008/03/27 03:57:33 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/bin/pg_dump/common.c,v 1.104 2008/05/09 23:32:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -62,8 +62,7 @@ static DumpableObject **oprinfoindex;
 
 static void flagInhTables(TableInfo *tbinfo, int numTables,
 			  InhInfo *inhinfo, int numInherits);
-static void flagInhAttrs(TableInfo *tbinfo, int numTables,
+static void flagInhAttrs(TableInfo *tblinfo, int numTables);
-			 InhInfo *inhinfo, int numInherits);
 static DumpableObject **buildIndexArray(void *objArray, int numObjs,
 				Size objSize);
 static int	DOCatalogIdCompare(const void *p1, const void *p2);
@@ -191,7 +190,7 @@ getSchemaData(int *numTablesPtr)
 
 	if (g_verbose)
 		write_msg(NULL, "flagging inherited columns in subtables\n");
-	flagInhAttrs(tblinfo, numTables, inhinfo, numInherits);
+	flagInhAttrs(tblinfo, numTables);
 
 	if (g_verbose)
 		write_msg(NULL, "reading indexes\n");
@@ -257,8 +256,7 @@ flagInhTables(TableInfo *tblinfo, int numTables,
  * modifies tblinfo
  */
 static void
-flagInhAttrs(TableInfo *tblinfo, int numTables,
+flagInhAttrs(TableInfo *tblinfo, int numTables)
-			 InhInfo *inhinfo, int numInherits)
 {
 	int			i,
 				j,
@@ -414,43 +412,6 @@ flagInhAttrs(TableInfo *tblinfo, int numTables,
 					tbinfo->inhAttrs[j] = false;
 			}
 		}
-
-		/*
-		 * Check for inherited CHECK constraints.  We assume a constraint is
-		 * inherited if its name matches the name of any constraint in the
-		 * parent.	Originally this code tried to compare the expression
-		 * texts, but that can fail if the parent and child tables are in
-		 * different schemas, because reverse-listing of function calls may
-		 * produce different text (schema-qualified or not) depending on
-		 * search path.  We really need a more bulletproof way of detecting
-		 * inherited constraints --- pg_constraint should record this
-		 * explicitly!
-		 */
-		for (j = 0; j < tbinfo->ncheck; j++)
-		{
-			ConstraintInfo *constr;
-
-			constr = &(tbinfo->checkexprs[j]);
-
-			for (k = 0; k < numParents; k++)
-			{
-				int			l;
-
-				parent = parents[k];
-				for (l = 0; l < parent->ncheck; l++)
-				{
-					ConstraintInfo *pconstr = &(parent->checkexprs[l]);
-
-					if (strcmp(pconstr->dobj.name, constr->dobj.name) == 0)
-					{
-						constr->coninherited = true;
-						break;
-					}
-				}
-				if (constr->coninherited)
-					break;
-			}
-		}
 	}
 }
 

src/bin/pg_dump/pg_dump.c

@@ -12,7 +12,7 @@
  *	by PostgreSQL
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.c,v 1.489 2008/05/03 23:32:32 adunstan Exp $
+ *	  $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.c,v 1.490 2008/05/09 23:32:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -120,6 +120,7 @@ static void expand_table_name_patterns(SimpleStringList *patterns,
 						   SimpleOidList *oids);
 static NamespaceInfo *findNamespace(Oid nsoid, Oid objoid);
 static void dumpTableData(Archive *fout, TableDataInfo *tdinfo);
+static void guessConstraintInheritance(TableInfo *tblinfo, int numTables);
 static void dumpComment(Archive *fout, const char *target,
 			const char *namespace, const char *owner,
 			CatalogId catalogId, int subid, DumpId dumpId);
@@ -645,6 +646,9 @@ main(int argc, char **argv)
 	 */
 	tblinfo = getSchemaData(&numTables);
 
+	if (g_fout->remoteVersion < 80400)
+		guessConstraintInheritance(tblinfo, numTables);
+
 	if (!schemaOnly)
 		getTableData(tblinfo, numTables, oids);
 
@@ -1383,6 +1387,81 @@ getTableData(TableInfo *tblinfo, int numTables, bool oids)
 }
 
 
+/*
+ * guessConstraintInheritance:
+ *	In pre-8.4 databases, we can't tell for certain which constraints
+ *	are inherited.  We assume a CHECK constraint is inherited if its name
+ *	matches the name of any constraint in the parent.  Originally this code
+ *	tried to compare the expression texts, but that can fail for various
+ *	reasons --- for example, if the parent and child tables are in different
+ *	schemas, reverse-listing of function calls may produce different text
+ *	(schema-qualified or not) depending on search path.
+ *
+ *	In 8.4 and up we can rely on the conislocal field to decide which
+ *	constraints must be dumped; much safer.
+ *
+ *	This function assumes all conislocal flags were initialized to TRUE.
+ *	It clears the flag on anything that seems to be inherited.
+ */
+static void
+guessConstraintInheritance(TableInfo *tblinfo, int numTables)
+{
+	int			i,
+				j,
+				k;
+
+	for (i = 0; i < numTables; i++)
+	{
+		TableInfo  *tbinfo = &(tblinfo[i]);
+		int			numParents;
+		TableInfo **parents;
+		TableInfo  *parent;
+
+		/* Sequences and views never have parents */
+		if (tbinfo->relkind == RELKIND_SEQUENCE ||
+			tbinfo->relkind == RELKIND_VIEW)
+			continue;
+
+		/* Don't bother computing anything for non-target tables, either */
+		if (!tbinfo->dobj.dump)
+			continue;
+
+		numParents = tbinfo->numParents;
+		parents = tbinfo->parents;
+
+		if (numParents == 0)
+			continue;			/* nothing to see here, move along */
+
+		/* scan for inherited CHECK constraints */
+		for (j = 0; j < tbinfo->ncheck; j++)
+		{
+			ConstraintInfo *constr;
+
+			constr = &(tbinfo->checkexprs[j]);
+
+			for (k = 0; k < numParents; k++)
+			{
+				int			l;
+
+				parent = parents[k];
+				for (l = 0; l < parent->ncheck; l++)
+				{
+					ConstraintInfo *pconstr = &(parent->checkexprs[l]);
+
+					if (strcmp(pconstr->dobj.name, constr->dobj.name) == 0)
+					{
+						constr->conislocal = false;
+						break;
+					}
+				}
+				if (!constr->conislocal)
+					break;
+			}
+		}
+	}
+}
+
+
 /*
  * dumpDatabase:
  *	dump the database definition
@@ -3522,7 +3601,7 @@ getIndexes(TableInfo tblinfo[], int numTables)
 				constrinfo[j].contype = contype;
 				constrinfo[j].condef = NULL;
 				constrinfo[j].conindex = indxinfo[j].dobj.dumpId;
-				constrinfo[j].coninherited = false;
+				constrinfo[j].conislocal = true;
 				constrinfo[j].separate = true;
 
 				indxinfo[j].indexconstraint = constrinfo[j].dobj.dumpId;
@@ -3623,7 +3702,7 @@ getConstraints(TableInfo tblinfo[], int numTables)
 			constrinfo[j].contype = 'f';
 			constrinfo[j].condef = strdup(PQgetvalue(res, j, i_condef));
 			constrinfo[j].conindex = 0;
-			constrinfo[j].coninherited = false;
+			constrinfo[j].conislocal = true;
 			constrinfo[j].separate = true;
 		}
 
@@ -3706,7 +3785,7 @@ getDomainConstraints(TypeInfo *tinfo)
 		constrinfo[i].contype = 'c';
 		constrinfo[i].condef = strdup(PQgetvalue(res, i, i_consrc));
 		constrinfo[i].conindex = 0;
-		constrinfo[i].coninherited = false;
+		constrinfo[i].conislocal = true;
 		constrinfo[i].separate = false;
 
 		/*
@@ -4586,10 +4665,22 @@ getTableAttrs(TableInfo *tblinfo, int numTables)
 						  tbinfo->dobj.name);
 
 			resetPQExpBuffer(q);
-			if (g_fout->remoteVersion >= 70400)
+			if (g_fout->remoteVersion >= 80400)
 			{
 				appendPQExpBuffer(q, "SELECT tableoid, oid, conname, "
-							"pg_catalog.pg_get_constraintdef(oid) AS consrc "
+							"pg_catalog.pg_get_constraintdef(oid) AS consrc, "
+								  "conislocal "
+								  "FROM pg_catalog.pg_constraint "
+								  "WHERE conrelid = '%u'::pg_catalog.oid "
+								  "   AND contype = 'c' "
+								  "ORDER BY conname",
+								  tbinfo->dobj.catId.oid);
+			}
+			else if (g_fout->remoteVersion >= 70400)
+			{
+				appendPQExpBuffer(q, "SELECT tableoid, oid, conname, "
+							"pg_catalog.pg_get_constraintdef(oid) AS consrc, "
+								  "true as conislocal "
 								  "FROM pg_catalog.pg_constraint "
 								  "WHERE conrelid = '%u'::pg_catalog.oid "
 								  "   AND contype = 'c' "
@@ -4600,7 +4691,8 @@ getTableAttrs(TableInfo *tblinfo, int numTables)
 			{
 				/* no pg_get_constraintdef, must use consrc */
 				appendPQExpBuffer(q, "SELECT tableoid, oid, conname, "
-								  "'CHECK (' || consrc || ')' AS consrc "
+								  "'CHECK (' || consrc || ')' AS consrc, "
+								  "true as conislocal "
 								  "FROM pg_catalog.pg_constraint "
 								  "WHERE conrelid = '%u'::pg_catalog.oid "
 								  "   AND contype = 'c' "
@@ -4612,7 +4704,8 @@ getTableAttrs(TableInfo *tblinfo, int numTables)
 				/* 7.2 did not have OIDs in pg_relcheck */
 				appendPQExpBuffer(q, "SELECT tableoid, 0 as oid, "
 								  "rcname AS conname, "
-								  "'CHECK (' || rcsrc || ')' AS consrc "
+								  "'CHECK (' || rcsrc || ')' AS consrc, "
+								  "true as conislocal "
 								  "FROM pg_relcheck "
 								  "WHERE rcrelid = '%u'::oid "
 								  "ORDER BY rcname",
@@ -4622,7 +4715,8 @@ getTableAttrs(TableInfo *tblinfo, int numTables)
 			{
 				appendPQExpBuffer(q, "SELECT tableoid, oid, "
 								  "rcname AS conname, "
-								  "'CHECK (' || rcsrc || ')' AS consrc "
+								  "'CHECK (' || rcsrc || ')' AS consrc, "
+								  "true as conislocal "
 								  "FROM pg_relcheck "
 								  "WHERE rcrelid = '%u'::oid "
 								  "ORDER BY rcname",
@@ -4634,7 +4728,8 @@ getTableAttrs(TableInfo *tblinfo, int numTables)
 				appendPQExpBuffer(q, "SELECT "
 								  "(SELECT oid FROM pg_class WHERE relname = 'pg_relcheck') AS tableoid, "
 								  "oid, rcname AS conname, "
-								  "'CHECK (' || rcsrc || ')' AS consrc "
+								  "'CHECK (' || rcsrc || ')' AS consrc, "
+								  "true as conislocal "
 								  "FROM pg_relcheck "
 								  "WHERE rcrelid = '%u'::oid "
 								  "ORDER BY rcname",
@@ -4668,7 +4763,7 @@ getTableAttrs(TableInfo *tblinfo, int numTables)
 				constrs[j].contype = 'c';
 				constrs[j].condef = strdup(PQgetvalue(res, j, 3));
 				constrs[j].conindex = 0;
-				constrs[j].coninherited = false;
+				constrs[j].conislocal = (PQgetvalue(res, j, 4)[0] == 't');
 				constrs[j].separate = false;
 
 				constrs[j].dobj.dump = tbinfo->dobj.dump;
@@ -4684,8 +4779,8 @@ getTableAttrs(TableInfo *tblinfo, int numTables)
 
 				/*
 				 * If the constraint is inherited, this will be detected
-				 * later.  We also detect later if the constraint must be
+				 * later (in pre-8.4 databases).  We also detect later if the
-				 * split out from the table definition.
+				 * constraint must be split out from the table definition.
 				 */
 			}
 			PQclear(res);
@@ -8840,7 +8935,7 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 		{
 			ConstraintInfo *constr = &(tbinfo->checkexprs[j]);
 
-			if (constr->coninherited || constr->separate)
+			if (constr->separate || !constr->conislocal)
 				continue;
 
 			if (actual_atts > 0)
@@ -8955,7 +9050,7 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
 	{
 		ConstraintInfo *constr = &(tbinfo->checkexprs[j]);
 
-		if (constr->coninherited || constr->separate)
+		if (constr->separate || !constr->conislocal)
 			continue;
 
 		dumpTableConstraintComment(fout, constr);

src/bin/pg_dump/pg_dump.h

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.h,v 1.139 2008/01/01 19:45:55 momjian Exp $
+ * $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.h,v 1.140 2008/05/09 23:32:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -353,7 +353,7 @@ typedef struct _constraintInfo
 	char		contype;
 	char	   *condef;			/* definition, if CHECK or FOREIGN KEY */
 	DumpId		conindex;		/* identifies associated index if any */
-	bool		coninherited;	/* TRUE if appears to be inherited */
+	bool		conislocal;		/* TRUE if constraint has local definition */
 	bool		separate;		/* TRUE if must dump as separate item */
 } ConstraintInfo;
 

src/include/catalog/catversion.h

@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.457 2008/05/08 08:58:59 mha Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.458 2008/05/09 23:32:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	200805081
+#define CATALOG_VERSION_NO	200805091
 
 #endif

src/include/catalog/heap.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/heap.h,v 1.87 2008/01/01 19:45:56 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/heap.h,v 1.88 2008/05/09 23:32:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -29,6 +29,8 @@ typedef struct CookedConstraint
 	char	   *name;			/* name, or NULL if none */
 	AttrNumber	attnum;			/* which attr (only for DEFAULT) */
 	Node	   *expr;			/* transformed default or check expr */
+	bool		is_local;		/* constraint has local (non-inherited) def */
+	int			inhcount;		/* number of times constraint is inherited */
 } CookedConstraint;
 
 extern Relation heap_create(const char *relname,
@@ -46,6 +48,7 @@ extern Oid heap_create_with_catalog(const char *relname,
 						 Oid relid,
 						 Oid ownerid,
 						 TupleDesc tupdesc,
+						 List *cooked_constraints,
 						 char relkind,
 						 bool shared_relation,
 						 bool oidislocal,
@@ -67,11 +70,13 @@ extern void InsertPgClassTuple(Relation pg_class_desc,
 				   Oid new_rel_oid,
 				   Datum reloptions);
 
-extern List *AddRelationRawConstraints(Relation rel,
+extern List *AddRelationNewConstraints(Relation rel,
-						  List *rawColDefaults,
+						  List *newColDefaults,
-						  List *rawConstraints);
+						  List *newConstraints,
+						  bool allow_merge,
+						  bool is_local);
 
-extern void StoreAttrDefault(Relation rel, AttrNumber attnum, char *adbin);
+extern void StoreAttrDefault(Relation rel, AttrNumber attnum, Node *expr);
 
 extern Node *cookDefault(ParseState *pstate,
 			Node *raw_default,
@@ -79,9 +84,6 @@ extern Node *cookDefault(ParseState *pstate,
 			int32 atttypmod,
 			char *attname);
 
-extern int RemoveRelConstraints(Relation rel, const char *constrName,
-					 DropBehavior behavior);
-
 extern void DeleteRelationTuple(Oid relid);
 extern void DeleteAttributeTuples(Oid relid);
 extern void RemoveAttributeById(Oid relid, AttrNumber attnum);

src/include/catalog/pg_constraint.h

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_constraint.h,v 1.28 2008/03/27 03:57:34 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_constraint.h,v 1.29 2008/05/09 23:32:04 tgl Exp $
  *
  * NOTES
  *	  the genbki.sh script reads this file and generates .bki
@@ -71,6 +71,12 @@ CATALOG(pg_constraint,2606)
 	char		confdeltype;	/* foreign key's ON DELETE action */
 	char		confmatchtype;	/* foreign key's match type */
 
+	/* Has a local definition (hence, do not drop when coninhcount is 0) */
+	bool		conislocal;
+
+	/* Number of times inherited from direct parent relation(s) */
+	int4		coninhcount;
+
 	/*
 	 * VARIABLE LENGTH FIELDS start here.  These fields may be NULL, too.
 	 */
@@ -125,7 +131,7 @@ typedef FormData_pg_constraint *Form_pg_constraint;
  *		compiler constants for pg_constraint
  * ----------------
  */
-#define Natts_pg_constraint					18
+#define Natts_pg_constraint					20
 #define Anum_pg_constraint_conname			1
 #define Anum_pg_constraint_connamespace		2
 #define Anum_pg_constraint_contype			3
@@ -137,13 +143,15 @@ typedef FormData_pg_constraint *Form_pg_constraint;
 #define Anum_pg_constraint_confupdtype		9
 #define Anum_pg_constraint_confdeltype		10
 #define Anum_pg_constraint_confmatchtype	11
-#define Anum_pg_constraint_conkey			12
+#define Anum_pg_constraint_conislocal		12
-#define Anum_pg_constraint_confkey			13
+#define Anum_pg_constraint_coninhcount		13
-#define Anum_pg_constraint_conpfeqop		14
+#define Anum_pg_constraint_conkey			14
-#define Anum_pg_constraint_conppeqop		15
+#define Anum_pg_constraint_confkey			15
-#define Anum_pg_constraint_conffeqop		16
+#define Anum_pg_constraint_conpfeqop		16
-#define Anum_pg_constraint_conbin			17
+#define Anum_pg_constraint_conppeqop		17
-#define Anum_pg_constraint_consrc			18
+#define Anum_pg_constraint_conffeqop		18
+#define Anum_pg_constraint_conbin			19
+#define Anum_pg_constraint_consrc			20
 
 
 /* Valid values for contype */
@@ -192,7 +200,9 @@ extern Oid CreateConstraintEntry(const char *constraintName,
 					  Oid indexRelId,
 					  Node *conExpr,
 					  const char *conBin,
-					  const char *conSrc);
+					  const char *conSrc,
+					  bool conIsLocal,
+					  int conInhCount);
 
 extern void RemoveConstraintById(Oid conId);
 extern void RenameConstraintById(Oid conId, const char *newname);

src/include/nodes/parsenodes.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.364 2008/04/29 20:44:49 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.365 2008/05/09 23:32:04 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -892,11 +892,11 @@ typedef enum AlterTableType
 	AT_AddIndex,				/* add index */
 	AT_ReAddIndex,				/* internal to commands/tablecmds.c */
 	AT_AddConstraint,			/* add constraint */
+	AT_AddConstraintRecurse,	/* internal to commands/tablecmds.c */
 	AT_ProcessedConstraint,		/* pre-processed add constraint (local in
 								 * parser/parse_utilcmd.c) */
 	AT_DropConstraint,			/* drop constraint */
-	AT_DropConstraintQuietly,	/* drop constraint, no error/warning (local in
+	AT_DropConstraintRecurse,	/* internal to commands/tablecmds.c */
-								 * commands/tablecmds.c) */
 	AT_AlterColumnType,			/* alter column type */
 	AT_ChangeOwner,				/* change owner */
 	AT_ClusterOn,				/* CLUSTER ON */

src/test/regress/expected/alter_table.out

@@ -378,19 +378,21 @@ drop table atacc2 cascade;
 NOTICE:  drop cascades to table atacc3
 NOTICE:  drop cascades to constraint foo on table atacc3
 drop table atacc1;
--- let's try only to add only to the parent
+-- adding only to a parent is disallowed as of 8.4
 create table atacc1 (test int);
-create table atacc2 (test2 int);
+create table atacc2 (test2 int) inherits (atacc1);
-create table atacc3 (test3 int) inherits (atacc1, atacc2);
+-- fail:
-alter table only atacc2 add constraint foo check (test2>0);
+alter table only atacc1 add constraint foo check (test>0);
--- fail and then succeed on atacc2
+ERROR:  constraint must be added to child tables too
-insert into atacc2 (test2) values (-3);
+-- ok:
+alter table only atacc2 add constraint foo check (test>0);
+-- check constraint not there on parent
+insert into atacc1 (test) values (-3);
+insert into atacc1 (test) values (3);
+-- check constraint is there on child
+insert into atacc2 (test) values (-3);
 ERROR:  new row for relation "atacc2" violates check constraint "foo"
-insert into atacc2 (test2) values (3);
+insert into atacc2 (test) values (3);
--- both succeed on atacc3
-insert into atacc3 (test2) values (-3);
-insert into atacc3 (test2) values (3);
-drop table atacc3;
 drop table atacc2;
 drop table atacc1;
 -- test unique constraint adding
@@ -1230,7 +1232,7 @@ alter table p1 add column f2 text;
 NOTICE:  merging definition of column "f2" for child "c1"
 insert into p1 values (1,2,'abc');
 insert into c1 values(11,'xyz',33,0); -- should fail
-ERROR:  new row for relation "c1" violates check constraint "c1_a1_check"
+ERROR:  new row for relation "c1" violates check constraint "p1_a1_check"
 insert into c1 values(11,'xyz',33,22);
 select * from p1;
  f1 | a1 | f2  
@@ -1249,7 +1251,7 @@ select * from p1;
 
 drop table p1 cascade;
 NOTICE:  drop cascades to table c1
-NOTICE:  drop cascades to constraint c1_a1_check on table c1
+NOTICE:  drop cascades to constraint p1_a1_check on table c1
 -- test that operations with a dropped column do not try to reference
 -- its datatype
 create domain mytype as text;

src/test/regress/expected/inherit.out

@@ -692,3 +692,220 @@ drop function p2text(p2);
 drop table c1;
 drop table p2;
 drop table p1;
+CREATE TABLE ac (aa TEXT);
+alter table ac add constraint ac_check check (aa is not null);
+CREATE TABLE bc (bb TEXT) INHERITS (ac);
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+ relname | conname  | contype | conislocal | coninhcount |      consrc      
+---------+----------+---------+------------+-------------+------------------
+ ac      | ac_check | c       | t          |           0 | (aa IS NOT NULL)
+ bc      | ac_check | c       | f          |           1 | (aa IS NOT NULL)
+(2 rows)
+
+insert into ac (aa) values (NULL);
+ERROR:  new row for relation "ac" violates check constraint "ac_check"
+insert into bc (aa) values (NULL);
+ERROR:  new row for relation "bc" violates check constraint "ac_check"
+alter table bc drop constraint ac_check;  -- fail, disallowed
+ERROR:  cannot drop inherited constraint "ac_check" of relation "bc"
+alter table ac drop constraint ac_check;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+ relname | conname | contype | conislocal | coninhcount | consrc 
+---------+---------+---------+------------+-------------+--------
+(0 rows)
+
+-- try the unnamed-constraint case
+alter table ac add check (aa is not null);
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+ relname |   conname   | contype | conislocal | coninhcount |      consrc      
+---------+-------------+---------+------------+-------------+------------------
+ ac      | ac_aa_check | c       | t          |           0 | (aa IS NOT NULL)
+ bc      | ac_aa_check | c       | f          |           1 | (aa IS NOT NULL)
+(2 rows)
+
+insert into ac (aa) values (NULL);
+ERROR:  new row for relation "ac" violates check constraint "ac_aa_check"
+insert into bc (aa) values (NULL);
+ERROR:  new row for relation "bc" violates check constraint "ac_aa_check"
+alter table bc drop constraint ac_aa_check;  -- fail, disallowed
+ERROR:  cannot drop inherited constraint "ac_aa_check" of relation "bc"
+alter table ac drop constraint ac_aa_check;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+ relname | conname | contype | conislocal | coninhcount | consrc 
+---------+---------+---------+------------+-------------+--------
+(0 rows)
+
+alter table ac add constraint ac_check check (aa is not null);
+alter table bc no inherit ac;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+ relname | conname  | contype | conislocal | coninhcount |      consrc      
+---------+----------+---------+------------+-------------+------------------
+ ac      | ac_check | c       | t          |           0 | (aa IS NOT NULL)
+ bc      | ac_check | c       | t          |           0 | (aa IS NOT NULL)
+(2 rows)
+
+alter table bc drop constraint ac_check;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+ relname | conname  | contype | conislocal | coninhcount |      consrc      
+---------+----------+---------+------------+-------------+------------------
+ ac      | ac_check | c       | t          |           0 | (aa IS NOT NULL)
+(1 row)
+
+alter table ac drop constraint ac_check;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+ relname | conname | contype | conislocal | coninhcount | consrc 
+---------+---------+---------+------------+-------------+--------
+(0 rows)
+
+drop table bc;
+drop table ac;
+create table ac (a int constraint check_a check (a <> 0));
+create table bc (a int constraint check_a check (a <> 0), b int constraint check_b check (b <> 0)) inherits (ac);
+NOTICE:  merging column "a" with inherited definition
+NOTICE:  merging constraint "check_a" with inherited definition
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+ relname | conname | contype | conislocal | coninhcount |  consrc  
+---------+---------+---------+------------+-------------+----------
+ ac      | check_a | c       | t          |           0 | (a <> 0)
+ bc      | check_a | c       | t          |           1 | (a <> 0)
+ bc      | check_b | c       | t          |           0 | (b <> 0)
+(3 rows)
+
+drop table bc;
+drop table ac;
+create table ac (a int constraint check_a check (a <> 0));
+create table bc (b int constraint check_b check (b <> 0));
+create table cc (c int constraint check_c check (c <> 0)) inherits (ac, bc);
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc', 'cc') order by 1,2;
+ relname | conname | contype | conislocal | coninhcount |  consrc  
+---------+---------+---------+------------+-------------+----------
+ ac      | check_a | c       | t          |           0 | (a <> 0)
+ bc      | check_b | c       | t          |           0 | (b <> 0)
+ cc      | check_a | c       | f          |           1 | (a <> 0)
+ cc      | check_b | c       | f          |           1 | (b <> 0)
+ cc      | check_c | c       | t          |           0 | (c <> 0)
+(5 rows)
+
+alter table cc no inherit bc;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc', 'cc') order by 1,2;
+ relname | conname | contype | conislocal | coninhcount |  consrc  
+---------+---------+---------+------------+-------------+----------
+ ac      | check_a | c       | t          |           0 | (a <> 0)
+ bc      | check_b | c       | t          |           0 | (b <> 0)
+ cc      | check_a | c       | f          |           1 | (a <> 0)
+ cc      | check_b | c       | t          |           0 | (b <> 0)
+ cc      | check_c | c       | t          |           0 | (c <> 0)
+(5 rows)
+
+drop table cc;
+drop table bc;
+drop table ac;
+create table p1(f1 int);
+create table p2(f2 int);
+create table c1(f3 int) inherits(p1,p2);
+insert into c1 values(1,-1,2);
+alter table p2 add constraint cc check (f2>0);  -- fail
+ERROR:  check constraint "cc" is violated by some row
+alter table p2 add check (f2>0);  -- check it without a name, too
+ERROR:  check constraint "p2_f2_check" is violated by some row
+delete from c1;
+insert into c1 values(1,1,2);
+alter table p2 add check (f2>0);
+insert into c1 values(1,-1,2);  -- fail
+ERROR:  new row for relation "c1" violates check constraint "p2_f2_check"
+create table c2(f3 int) inherits(p1,p2);
+\d c2
+      Table "public.c2"
+ Column |  Type   | Modifiers 
+--------+---------+-----------
+ f1     | integer |          
+ f2     | integer |          
+ f3     | integer |          
+Check constraints:
+    "p2_f2_check" CHECK (f2 > 0)
+Inherits: p1,
+          p2
+
+create table c3 (f4 int) inherits(c1,c2);
+NOTICE:  merging multiple inherited definitions of column "f1"
+NOTICE:  merging multiple inherited definitions of column "f2"
+NOTICE:  merging multiple inherited definitions of column "f3"
+\d c3
+      Table "public.c3"
+ Column |  Type   | Modifiers 
+--------+---------+-----------
+ f1     | integer |          
+ f2     | integer |          
+ f3     | integer |          
+ f4     | integer |          
+Check constraints:
+    "p2_f2_check" CHECK (f2 > 0)
+Inherits: c1,
+          c2
+
+drop table p1 cascade;
+NOTICE:  drop cascades to table c2
+NOTICE:  drop cascades to table c3
+NOTICE:  drop cascades to constraint p2_f2_check on table c3
+NOTICE:  drop cascades to constraint p2_f2_check on table c2
+NOTICE:  drop cascades to table c1
+NOTICE:  drop cascades to constraint p2_f2_check on table c1
+drop table p2 cascade;
+create table pp1 (f1 int);
+create table cc1 (f2 text, f3 int) inherits (pp1);
+alter table pp1 add column a1 int check (a1 > 0);
+\d cc1
+      Table "public.cc1"
+ Column |  Type   | Modifiers 
+--------+---------+-----------
+ f1     | integer |          
+ f2     | text    |          
+ f3     | integer |          
+ a1     | integer |          
+Check constraints:
+    "pp1_a1_check" CHECK (a1 > 0)
+Inherits: pp1
+
+create table cc2(f4 float) inherits(pp1,cc1);
+NOTICE:  merging multiple inherited definitions of column "f1"
+NOTICE:  merging multiple inherited definitions of column "a1"
+\d cc2
+          Table "public.cc2"
+ Column |       Type       | Modifiers 
+--------+------------------+-----------
+ f1     | integer          |          
+ a1     | integer          |          
+ f2     | text             |          
+ f3     | integer          |          
+ f4     | double precision |          
+Check constraints:
+    "pp1_a1_check" CHECK (a1 > 0)
+Inherits: pp1,
+          cc1
+
+alter table pp1 add column a2 int check (a2 > 0);
+NOTICE:  merging definition of column "a2" for child "cc2"
+NOTICE:  merging constraint "pp1_a2_check" with inherited definition
+\d cc2
+          Table "public.cc2"
+ Column |       Type       | Modifiers 
+--------+------------------+-----------
+ f1     | integer          |          
+ a1     | integer          |          
+ f2     | text             |          
+ f3     | integer          |          
+ f4     | double precision |          
+ a2     | integer          |          
+Check constraints:
+    "pp1_a1_check" CHECK (a1 > 0)
+    "pp1_a2_check" CHECK (a2 > 0)
+Inherits: pp1,
+          cc1
+
+drop table pp1 cascade;
+NOTICE:  drop cascades to table cc2
+NOTICE:  drop cascades to constraint pp1_a1_check on table cc2
+NOTICE:  drop cascades to constraint pp1_a2_check on table cc2
+NOTICE:  drop cascades to table cc1
+NOTICE:  drop cascades to constraint pp1_a1_check on table cc1
+NOTICE:  drop cascades to constraint pp1_a2_check on table cc1

src/test/regress/sql/alter_table.sql

@@ -389,19 +389,20 @@ select test2 from atacc2;
 drop table atacc2 cascade;
 drop table atacc1;
 
--- let's try only to add only to the parent
+-- adding only to a parent is disallowed as of 8.4
 
 create table atacc1 (test int);
-create table atacc2 (test2 int);
+create table atacc2 (test2 int) inherits (atacc1);
-create table atacc3 (test3 int) inherits (atacc1, atacc2);
+-- fail:
-alter table only atacc2 add constraint foo check (test2>0);
+alter table only atacc1 add constraint foo check (test>0);
--- fail and then succeed on atacc2
+-- ok:
-insert into atacc2 (test2) values (-3);
+alter table only atacc2 add constraint foo check (test>0);
-insert into atacc2 (test2) values (3);
+-- check constraint not there on parent
--- both succeed on atacc3
+insert into atacc1 (test) values (-3);
-insert into atacc3 (test2) values (-3);
+insert into atacc1 (test) values (3);
-insert into atacc3 (test2) values (3);
+-- check constraint is there on child
-drop table atacc3;
+insert into atacc2 (test) values (-3);
+insert into atacc2 (test) values (3);
 drop table atacc2;
 drop table atacc1;
 

src/test/regress/sql/inherit.sql

@@ -196,3 +196,83 @@ drop function p2text(p2);
 drop table c1;
 drop table p2;
 drop table p1;
+
+CREATE TABLE ac (aa TEXT);
+alter table ac add constraint ac_check check (aa is not null);
+CREATE TABLE bc (bb TEXT) INHERITS (ac);
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+
+insert into ac (aa) values (NULL);
+insert into bc (aa) values (NULL);
+
+alter table bc drop constraint ac_check;  -- fail, disallowed
+alter table ac drop constraint ac_check;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+
+-- try the unnamed-constraint case
+alter table ac add check (aa is not null);
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+
+insert into ac (aa) values (NULL);
+insert into bc (aa) values (NULL);
+
+alter table bc drop constraint ac_aa_check;  -- fail, disallowed
+alter table ac drop constraint ac_aa_check;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+
+alter table ac add constraint ac_check check (aa is not null);
+alter table bc no inherit ac;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+alter table bc drop constraint ac_check;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+alter table ac drop constraint ac_check;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+
+drop table bc;
+drop table ac;
+
+create table ac (a int constraint check_a check (a <> 0));
+create table bc (a int constraint check_a check (a <> 0), b int constraint check_b check (b <> 0)) inherits (ac);
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+
+drop table bc;
+drop table ac;
+
+create table ac (a int constraint check_a check (a <> 0));
+create table bc (b int constraint check_b check (b <> 0));
+create table cc (c int constraint check_c check (c <> 0)) inherits (ac, bc);
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc', 'cc') order by 1,2;
+
+alter table cc no inherit bc;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc', 'cc') order by 1,2;
+
+drop table cc;
+drop table bc;
+drop table ac;
+
+create table p1(f1 int);
+create table p2(f2 int);
+create table c1(f3 int) inherits(p1,p2);
+insert into c1 values(1,-1,2);
+alter table p2 add constraint cc check (f2>0);  -- fail
+alter table p2 add check (f2>0);  -- check it without a name, too
+delete from c1;
+insert into c1 values(1,1,2);
+alter table p2 add check (f2>0);
+insert into c1 values(1,-1,2);  -- fail
+create table c2(f3 int) inherits(p1,p2);
+\d c2
+create table c3 (f4 int) inherits(c1,c2);
+\d c3
+drop table p1 cascade;
+drop table p2 cascade;
+
+create table pp1 (f1 int);
+create table cc1 (f2 text, f3 int) inherits (pp1);
+alter table pp1 add column a1 int check (a1 > 0);
+\d cc1
+create table cc2(f4 float) inherits(pp1,cc1);
+\d cc2
+alter table pp1 add column a2 int check (a2 > 0);
+\d cc2
+drop table pp1 cascade;