Reimplement parsing and storage of default expressions and constraint

expressions in CREATE TABLE.  There is no longer an emasculated expression
syntax for these things; it's full a_expr for constraints, and b_expr
for defaults (unfortunately the fact that NOT NULL is a part of the
column constraint syntax causes a shift/reduce conflict if you try a_expr.
Oh well --- at least parenthesized boolean expressions work now).  Also,
stored expression for a column default is not pre-coerced to the column
type; we rely on transformInsertStatement to do that when the default is
actually used.  This means "f1 datetime default 'now'" behaves the way
people usually expect it to.
BTW, all the support code is now there to implement ALTER TABLE ADD
CONSTRAINT and ALTER TABLE ADD COLUMN with a default value.  I didn't
actually teach ALTER TABLE to call it, but it wouldn't be much work.

1 files changed, 12 insertions, 17 deletions

diff --git a/src/backend/access/common/tupdesc.c b/src/backend/access/common/tupdesc.c
index 4bce6ee914f..f0e717445a6 100644
--- a/src/backend/access/common/tupdesc.c
+++ b/src/backend/access/common/tupdesc.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/common/tupdesc.c,v 1.54 1999/07/17 20:16:36 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/common/tupdesc.c,v 1.55 1999/10/03 23:55:25 tgl Exp $
  *
  * NOTES
  *	  some of the executor utility code such as "ExecTypeFromTL" should be
@@ -160,8 +160,6 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 			{
 				if (constr->defval[i].adbin)
 					cpy->defval[i].adbin = pstrdup(constr->defval[i].adbin);
-				if (constr->defval[i].adsrc)
-					cpy->defval[i].adsrc = pstrdup(constr->defval[i].adsrc);
 			}
 		}
 
@@ -175,8 +173,6 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
 					cpy->check[i].ccname = pstrdup(constr->check[i].ccname);
 				if (constr->check[i].ccbin)
 					cpy->check[i].ccbin = pstrdup(constr->check[i].ccbin);
-				if (constr->check[i].ccsrc)
-					cpy->check[i].ccsrc = pstrdup(constr->check[i].ccsrc);
 			}
 		}
 
@@ -206,8 +202,6 @@ FreeTupleDesc(TupleDesc tupdesc)
 			{
 				if (attrdef[i].adbin)
 					pfree(attrdef[i].adbin);
-				if (attrdef[i].adsrc)
-					pfree(attrdef[i].adsrc);
 			}
 			pfree(attrdef);
 		}
@@ -221,8 +215,6 @@ FreeTupleDesc(TupleDesc tupdesc)
 					pfree(check[i].ccname);
 				if (check[i].ccbin)
 					pfree(check[i].ccbin);
-				if (check[i].ccsrc)
-					pfree(check[i].ccsrc);
 			}
 			pfree(check);
 		}
@@ -438,7 +430,7 @@ BuildDescForRelation(List *schema, char *relname)
 	AttrDefault *attrdef = NULL;
 	TupleConstr *constr = (TupleConstr *) palloc(sizeof(TupleConstr));
 	char	   *attname;
-	char	   *typename;
+	char		typename[NAMEDATALEN];
 	int32		atttypmod;
 	int			attdim;
 	int			ndef = 0;
@@ -454,11 +446,9 @@ BuildDescForRelation(List *schema, char *relname)
 
 	attnum = 0;
 
-	typename = palloc(NAMEDATALEN);
-
 	foreach(p, schema)
 	{
-		ColumnDef  *entry;
+		ColumnDef  *entry = lfirst(p);
 		List	   *arry;
 
 		/* ----------------
@@ -469,7 +459,6 @@ BuildDescForRelation(List *schema, char *relname)
 		 */
 		attnum++;
 
-		entry = lfirst(p);
 		attname = entry->colname;
 		arry = entry->typename->arrayBounds;
 		attisset = entry->typename->setof;
@@ -513,13 +502,15 @@ BuildDescForRelation(List *schema, char *relname)
 			constr->has_not_null = true;
 		desc->attrs[attnum - 1]->attnotnull = entry->is_not_null;
 
-		if (entry->defval != 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 = NULL;
-			attrdef[ndef].adsrc = entry->defval;
+			attrdef[ndef].adbin = pstrdup(entry->cooked_default);
 			ndef++;
 			desc->attrs[attnum - 1]->atthasdef = true;
 		}
@@ -539,7 +530,11 @@ BuildDescForRelation(List *schema, char *relname)
 			constr->num_defval = ndef;
 		}
 		else
+		{
+			constr->defval = NULL;
 			constr->num_defval = 0;
+		}
+		constr->check = NULL;
 		constr->num_check = 0;
 	}
 	else