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Use the dependency mechanism to manage column defaults. We need this

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so that dependencies in default expressions (on operators, functions,
etc) can be expressed properly.
This commit is contained in:
Tom Lane
2002-07-15 16:33:32 +00:00
parent 3c580b8d97
commit 7bd631bfa4
8 changed files with 307 additions and 191 deletions
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77
src/backend/commands/tablecmds.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.20 2002/07/12 18:43:16 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.21 2002/07/15 16:33:31 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -23,7 +23,6 @@
#include "catalog/index.h"
#include "catalog/indexing.h"
#include "catalog/namespace.h"
#include "catalog/pg_attrdef.h"
#include "catalog/pg_constraint.h"
#include "catalog/pg_inherits.h"
#include "catalog/pg_namespace.h"
@ -57,7 +56,6 @@ static bool change_varattnos_of_a_node(Node *node, const AttrNumber *newattno);
static void StoreCatalogInheritance(Oid relationId, List *supers);
static int findAttrByName(const char *attributeName, List *schema);
static void setRelhassubclassInRelation(Oid relationId, bool relhassubclass);
static void drop_default(Oid relid, int16 attnum);
static void CheckTupleType(Form_pg_class tuple_class);
static bool needs_toast_table(Relation rel);
static void validateForeignKeyConstraint(FkConstraint *fkconstraint,
@ -2080,14 +2078,18 @@ AlterTableAlterColumnDefault(Oid myrelid,
attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
ReleaseSysCache(tuple);
/*
* Remove any old default for the column. We use RESTRICT here for
* safety, but at present we do not expect anything to depend on the
* default.
*/
RemoveAttrDefault(myrelid, attnum, DROP_RESTRICT, false);
if (newDefault)
{
/* SET DEFAULT */
RawColumnDefault *rawEnt;
/* Get rid of the old one first */
drop_default(myrelid, attnum);
rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
rawEnt->attnum = attnum;
rawEnt->raw_default = newDefault;
@ -2098,73 +2100,10 @@ AlterTableAlterColumnDefault(Oid myrelid,
*/
AddRelationRawConstraints(rel, makeList1(rawEnt), NIL);
}
else
{
/* DROP DEFAULT */
Relation attr_rel;
/* Fix the pg_attribute row */
attr_rel = heap_openr(AttributeRelationName, RowExclusiveLock);
tuple = SearchSysCacheCopy(ATTNAME,
ObjectIdGetDatum(myrelid),
PointerGetDatum(colName),
0, 0);
if (!HeapTupleIsValid(tuple)) /* shouldn't happen */
elog(ERROR, "ALTER TABLE: relation \"%s\" has no column \"%s\"",
RelationGetRelationName(rel), colName);
((Form_pg_attribute) GETSTRUCT(tuple))->atthasdef = FALSE;
simple_heap_update(attr_rel, &tuple->t_self, tuple);
/* keep the system catalog indices current */
if (RelationGetForm(attr_rel)->relhasindex)
{
Relation idescs[Num_pg_attr_indices];
CatalogOpenIndices(Num_pg_attr_indices, Name_pg_attr_indices, idescs);
CatalogIndexInsert(idescs, Num_pg_attr_indices, attr_rel, tuple);
CatalogCloseIndices(Num_pg_attr_indices, idescs);
}
heap_close(attr_rel, RowExclusiveLock);
/* get rid of actual default definition in pg_attrdef */
drop_default(myrelid, attnum);
}
heap_close(rel, NoLock);
}
static void
drop_default(Oid relid, int16 attnum)
{
ScanKeyData scankeys[2];
HeapScanDesc scan;
Relation attrdef_rel;
HeapTuple tuple;
attrdef_rel = heap_openr(AttrDefaultRelationName, RowExclusiveLock);
ScanKeyEntryInitialize(&scankeys[0], 0x0,
Anum_pg_attrdef_adrelid, F_OIDEQ,
ObjectIdGetDatum(relid));
ScanKeyEntryInitialize(&scankeys[1], 0x0,
Anum_pg_attrdef_adnum, F_INT2EQ,
Int16GetDatum(attnum));
scan = heap_beginscan(attrdef_rel, SnapshotNow, 2, scankeys);
if ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
simple_heap_delete(attrdef_rel, &tuple->t_self);
heap_endscan(scan);
heap_close(attrdef_rel, NoLock);
}
/*
* ALTER TABLE ALTER COLUMN SET STATISTICS / STORAGE
*/