From 306ada82c2d73cc09a42ef2ac2934722c0674b80 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter_e@gmx.net>
Date: Mon, 24 Jan 2000 23:40:35 +0000
Subject: [PATCH] Removed alter table drop column.
---
src/backend/commands/command.c | 200 +--------------------------------
1 file changed, 2 insertions(+), 198 deletions(-)
diff --git a/src/backend/commands/command.c b/src/backend/commands/command.c
index 5c29dd692ac..ac7226c959a 100644
--- a/src/backend/commands/command.c
+++ b/src/backend/commands/command.c
@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.64 2000/01/22 14:20:45 petere Exp $
+ * $Header: /cvsroot/pgsql/src/backend/commands/Attic/command.c,v 1.65 2000/01/24 23:40:35 petere Exp $
*
* NOTES
* The PortalExecutorHeapMemory crap needs to be eliminated
@@ -672,209 +672,13 @@ drop_default(Oid relid, int16 attnum)
/*
* ALTER TABLE DROP COLUMN
- *
- * Strategy:
- * - permission/sanity checks
- * - create a new table _ATDC<name> with all attributes minus the desired one
- * - copy over all the data
- * - make the column defaults point to the new table
- * - kill the old table
- * - rename the intermediate table back
*/
void
AlterTableDropColumn(const char *relationName,
bool inh, const char *colName,
int behavior)
{
- Relation oldrel, newrel, defrel;
- HeapTuple tuple;
- TupleDesc olddesc, newdesc, defdsc;
- int16 dropattnum, oldnumatts;
- Oid oldrel_oid, newrel_oid;
- char tmpname[NAMEDATALEN];
- int16 i;
- HeapScanDesc scan;
- ScanKeyData scankey;
-
- if (!allowSystemTableMods && IsSystemRelationName(relationName))
- elog(ERROR, "ALTER TABLE: relation \"%s\" is a system catalog",
- relationName);
-#ifndef NO_SECURITY
- if (!pg_ownercheck(UserName, relationName, RELNAME))
- elog(ERROR, "ALTER TABLE: permission denied");
-#endif
-
- oldrel = heap_openr(relationName, AccessExclusiveLock);
- if (oldrel->rd_rel->relkind != RELKIND_RELATION)
- {
- heap_close(oldrel, AccessExclusiveLock);
- elog(ERROR, "ALTER TABLE: relation %s is not a table", relationName);
- }
-
- oldrel_oid = ObjectIdGetDatum(RelationGetRelid(oldrel));
- oldnumatts = RelationGetNumberOfAttributes(oldrel);
-
- if (oldnumatts==1)
- {
- heap_close(oldrel, AccessExclusiveLock);
- elog(ERROR, "ALTER TABLE: relation %s only has one column", relationName);
- }
-
-/* What to do here? */
-/*
- if (length(find_all_inheritors(RelationGetRelid(oldrel)))>0)
- elog(ERROR, "ALTER TABLE: cannot drop a column on table that is inherited from");
-*/
- /*
- * get the number of the attribute
- */
- tuple = SearchSysCacheTuple(ATTNAME, oldrel_oid, NameGetDatum(namein(colName)), 0, 0);
- if (!HeapTupleIsValid(tuple))
- {
- heap_close(oldrel, AccessExclusiveLock);
- elog(ERROR, "ALTER TABLE: relation \"%s\" has no column \"%s\"",
- relationName, colName);
- }
-
- dropattnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
-
- if (snprintf(tmpname, NAMEDATALEN, "_ATDC%s", relationName)==-1)
- {
- heap_close(oldrel, AccessExclusiveLock);
- elog(ERROR, "AlterTableDropColumn: relation name too long");
- }
-
- /*
- * Build descriptor for new relation
- */
- olddesc = RelationGetDescr(oldrel);
-
- newdesc = CreateTemplateTupleDesc(oldnumatts-1);
- for(i = 1; i < dropattnum; i++)
- {
- Form_pg_attribute att = olddesc->attrs[i-1];
- TupleDescInitEntry(newdesc, i, nameout(&(att->attname)),
- att->atttypid, att->atttypmod,
- att->attnelems, att->attisset);
- /* the above function doesn't take care of these two */
- newdesc->attrs[i-1]->attnotnull = att->attnotnull;
- newdesc->attrs[i-1]->atthasdef = att->atthasdef;
- }
-
- for(i = dropattnum; i <= oldnumatts-1; i++)
- {
- Form_pg_attribute att = olddesc->attrs[i];
- TupleDescInitEntry(newdesc, i, nameout(&(att->attname)),
- att->atttypid, att->atttypmod,
- att->attnelems, att->attisset);
- /* the above function doesn't take care of these two */
- newdesc->attrs[i-1]->attnotnull = att->attnotnull;
- newdesc->attrs[i-1]->atthasdef = att->atthasdef;
- }
-
- /* Create the new table */
- newrel_oid = heap_create_with_catalog(tmpname, newdesc, RELKIND_RELATION, false);
- if (newrel_oid == InvalidOid)
- {
- heap_close(oldrel, AccessExclusiveLock);
- elog(ERROR, "ALTER TABLE: something went wrong");
- }
-
- /* Make the new table visible */
- CommandCounterIncrement();
-
- /*
- * Copy over the data
- */
- newrel = heap_open(newrel_oid, AccessExclusiveLock);
-
- scan = heap_beginscan(oldrel, false, SnapshotNow, 0, NULL);
- while (HeapTupleIsValid(tuple = heap_getnext(scan, 0)))
- {
- bool isnull;
- Datum *new_record;
- bool *new_record_nulls;
- HeapTuple new_tuple;
-
- new_record = palloc((oldnumatts-1) * sizeof(*new_record));
- new_record_nulls = palloc((oldnumatts-1) * sizeof(*new_record_nulls));
-
- for(i = 1; i < dropattnum; i++)
- {
- new_record[i-1] = heap_getattr(tuple, i, olddesc, &isnull);
- new_record_nulls[i-1] = isnull ? 'n' : ' ';
- }
- for(i = dropattnum+1; i <= oldnumatts; i++)
- {
- new_record[i-2] = heap_getattr(tuple, i, olddesc, &isnull);
- new_record_nulls[i-2] = isnull ? 'n' : ' ';
- }
-
- new_tuple = heap_formtuple(newdesc, new_record, new_record_nulls);
- Assert(new_tuple);
-
- if (heap_insert(newrel, new_tuple) == InvalidOid)
- elog(ERROR, "AlterTableDropColumn: heap_insert failed");
-
- pfree(new_record);
- pfree(new_record_nulls);
- }
- heap_endscan(scan);
-
- heap_close(newrel, NoLock);
- heap_close(oldrel, NoLock);
-
- /*
- * Move defaults over to the new table
- */
- defrel = heap_openr(AttrDefaultRelationName, AccessExclusiveLock);
- defdsc = RelationGetDescr(defrel);
-
- /* look for all entries referencing the old table */
- ScanKeyEntryInitialize(&scankey, 0x0, Anum_pg_attrdef_adrelid, F_OIDEQ,
- ObjectIdGetDatum(oldrel_oid));
- scan = heap_beginscan(defrel, false, SnapshotNow, 1, &scankey);
- while(HeapTupleIsValid(tuple = heap_getnext(scan, false)))
- {
- HeapTuple newtuple;
- int2 attrnum;
- Relation irelations[Num_pg_attrdef_indices];
-
- attrnum = ((Form_pg_attrdef) GETSTRUCT(tuple))->adnum;
-
- /* remove the entry about the dropped column */
- if (attrnum == dropattnum)
- {
- heap_delete(defrel, &tuple->t_self, NULL);
- continue;
- }
-
- newtuple = heap_copytuple(tuple);
-
- if (attrnum > dropattnum)
- ((Form_pg_attrdef) GETSTRUCT(newtuple))->adnum--;
-
- /* make it point to the new table */
- ((Form_pg_attrdef) GETSTRUCT(newtuple))->adrelid = newrel_oid;
- heap_update(defrel, &tuple->t_self, newtuple, NULL);
-
- /* keep the system catalog indices current */
- CatalogOpenIndices(Num_pg_attrdef_indices, Name_pg_attrdef_indices, irelations);
- CatalogIndexInsert(irelations, Num_pg_attrdef_indices, defrel, newtuple);
- CatalogCloseIndices(Num_pg_attrdef_indices, irelations);
- }
- heap_endscan(scan);
- heap_close(defrel, NoLock);
-
- CommandCounterIncrement();
-
- /* make the old table disappear */
- heap_drop_with_catalog(relationName);
- CommandCounterIncrement();
-
- /* set back original name */
- TypeRename(tmpname, relationName);
- renamerel(tmpname, relationName);
+ elog(ERROR, "ALTER TABLE / DROP COLUMN is not implemented");
}
--
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