Clean up generation of default names for constraints, indexes, and serial

sequences, as per recent discussion.  All these names are now of the
form table_column_type, with digits added if needed to make them unique.
Default constraint names are chosen to be unique across their whole schema,
not just within the parent object, so as to be more SQL-spec-compatible
and make the information schema views more useful.

1 files changed, 31 insertions, 43 deletions

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 3a95064442c..7b0b35840ee 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.112 2004/06/06 20:30:07 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.113 2004/06/10 17:55:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -124,8 +124,6 @@ typedef struct AlteredTableInfo
 	List	   *changedConstraintDefs;	/* string definitions of same */
 	List	   *changedIndexOids;	/* OIDs of indexes to rebuild */
 	List	   *changedIndexDefs;	/* string definitions of same */
-	/* Workspace for ATExecAddConstraint */
-	int			constr_name_ctr;
 } AlteredTableInfo;
 
 /* Struct describing one new constraint to check in Phase 3 scan */
@@ -323,46 +321,45 @@ DefineRelation(CreateStmt *stmt, char relkind)
 
 	if (old_constraints != NIL)
 	{
-		ConstrCheck *check = (ConstrCheck *) palloc(list_length(old_constraints) *
-													sizeof(ConstrCheck));
+		ConstrCheck *check = (ConstrCheck *)
+			palloc0(list_length(old_constraints) * sizeof(ConstrCheck));
 		int			ncheck = 0;
-		int			constr_name_ctr = 0;
 
 		foreach(listptr, old_constraints)
 		{
 			Constraint *cdef = (Constraint *) lfirst(listptr);
+			bool dup = false;
 
 			if (cdef->contype != CONSTR_CHECK)
 				continue;
-
-			if (cdef->name != NULL)
+			Assert(cdef->name != NULL);
+			Assert(cdef->raw_expr == NULL && cdef->cooked_expr != NULL);
+			/*
+			 * In multiple-inheritance situations, it's possible to inherit
+			 * the same grandparent constraint through multiple parents.
+			 * Hence, discard inherited constraints that match as to both
+			 * name and expression.  Otherwise, gripe if the names conflict.
+			 */
+			for (i = 0; i < ncheck; i++)
 			{
-				for (i = 0; i < ncheck; i++)
+				if (strcmp(check[i].ccname, cdef->name) != 0)
+					continue;
+				if (strcmp(check[i].ccbin, cdef->cooked_expr) == 0)
 				{
-					if (strcmp(check[i].ccname, cdef->name) == 0)
-						ereport(ERROR,
-								(errcode(ERRCODE_DUPLICATE_OBJECT),
+					dup = true;
+					break;
+				}
+				ereport(ERROR,
+						(errcode(ERRCODE_DUPLICATE_OBJECT),
 						 errmsg("duplicate check constraint name \"%s\"",
 								cdef->name)));
-				}
-				check[ncheck].ccname = cdef->name;
 			}
-			else
+			if (!dup)
 			{
-				/*
-				 * Generate a constraint name.	NB: this should match the
-				 * form of names that GenerateConstraintName() may produce
-				 * for names added later.  We are assured that there is no
-				 * name conflict, because MergeAttributes() did not pass
-				 * back any names of this form.
-				 */
-				check[ncheck].ccname = (char *) palloc(NAMEDATALEN);
-				snprintf(check[ncheck].ccname, NAMEDATALEN, "$%d",
-						 ++constr_name_ctr);
+				check[ncheck].ccname = cdef->name;
+				check[ncheck].ccbin = pstrdup(cdef->cooked_expr);
+				ncheck++;
 			}
-			Assert(cdef->raw_expr == NULL && cdef->cooked_expr != NULL);
-			check[ncheck].ccbin = pstrdup(cdef->cooked_expr);
-			ncheck++;
 		}
 		if (ncheck > 0)
 		{
@@ -867,17 +864,7 @@ MergeAttributes(List *schema, List *supers, bool istemp,
 				Node	   *expr;
 
 				cdef->contype = CONSTR_CHECK;
-
-				/*
-				 * Do not inherit generated constraint names, since they
-				 * might conflict across multiple inheritance parents.
-				 * (But conflicts between user-assigned names will cause
-				 * an error.)
-				 */
-				if (ConstraintNameIsGenerated(check[i].ccname))
-					cdef->name = NULL;
-				else
-					cdef->name = pstrdup(check[i].ccname);
+				cdef->name = pstrdup(check[i].ccname);
 				cdef->raw_expr = NULL;
 				/* adjust varattnos of ccbin here */
 				expr = stringToNode(check[i].ccbin);
@@ -3610,10 +3597,11 @@ ATExecAddConstraint(AlteredTableInfo *tab, Relation rel, Node *newConstraint)
 			}
 			else
 				fkconstraint->constr_name =
-					GenerateConstraintName(CONSTRAINT_RELATION,
-										   RelationGetRelid(rel),
-										   RelationGetNamespace(rel),
-										   &tab->constr_name_ctr);
+					ChooseConstraintName(RelationGetRelationName(rel),
+										 strVal(linitial(fkconstraint->fk_attrs)),
+										 "fkey",
+										 RelationGetNamespace(rel),
+										 NIL);
 
 			ATAddForeignKeyConstraint(tab, rel, fkconstraint);