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Make the world at least somewhat safe for zero-column tables, and

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remove the special case in ALTER DROP COLUMN to prohibit dropping a
table's last column.
This commit is contained in:
Tom Lane
2002-09-28 20:00:19 +00:00
parent 23616b47d5
commit 6d0d15c451
6 changed files with 64 additions and 81 deletions
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65
src/backend/access/common/tupdesc.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/common/tupdesc.c,v 1.90 2002/09/22 19:42:50 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/access/common/tupdesc.c,v 1.91 2002/09/28 20:00:18 tgl Exp $
*
* NOTES
* some of the executor utility code such as "ExecTypeFromTL" should be
@ -39,28 +39,34 @@
TupleDesc
CreateTemplateTupleDesc(int natts, bool hasoid)
{
uint32 size;
TupleDesc desc;
/*
* sanity checks
*/
AssertArg(natts >= 1);
AssertArg(natts >= 0);
/*
* allocate enough memory for the tuple descriptor and zero it as
* TupleDescInitEntry assumes that the descriptor is filled with NULL
* pointers.
*/
size = natts * sizeof(Form_pg_attribute);
desc = (TupleDesc) palloc(sizeof(struct tupleDesc));
desc->attrs = (Form_pg_attribute *) palloc(size);
desc->constr = NULL;
MemSet(desc->attrs, 0, size);
desc->natts = natts;
desc->tdhasoid = hasoid;
if (natts > 0)
{
uint32 size = natts * sizeof(Form_pg_attribute);
desc->attrs = (Form_pg_attribute *) palloc(size);
MemSet(desc->attrs, 0, size);
}
else
desc->attrs = NULL;
desc->constr = NULL;
return desc;
}
@ -79,7 +85,7 @@ CreateTupleDesc(int natts, bool hasoid, Form_pg_attribute *attrs)
/*
* sanity checks
*/
AssertArg(natts >= 1);
AssertArg(natts >= 0);
desc = (TupleDesc) palloc(sizeof(struct tupleDesc));
desc->attrs = attrs;
@ -108,17 +114,20 @@ CreateTupleDescCopy(TupleDesc tupdesc)
desc = (TupleDesc) palloc(sizeof(struct tupleDesc));
desc->natts = tupdesc->natts;
size = desc->natts * sizeof(Form_pg_attribute);
desc->attrs = (Form_pg_attribute *) palloc(size);
for (i = 0; i < desc->natts; i++)
if (desc->natts > 0)
{
desc->attrs[i] = (Form_pg_attribute) palloc(ATTRIBUTE_TUPLE_SIZE);
memcpy(desc->attrs[i],
tupdesc->attrs[i],
ATTRIBUTE_TUPLE_SIZE);
desc->attrs[i]->attnotnull = false;
desc->attrs[i]->atthasdef = false;
size = desc->natts * sizeof(Form_pg_attribute);
desc->attrs = (Form_pg_attribute *) palloc(size);
for (i = 0; i < desc->natts; i++)
{
desc->attrs[i] = (Form_pg_attribute) palloc(ATTRIBUTE_TUPLE_SIZE);
memcpy(desc->attrs[i], tupdesc->attrs[i], ATTRIBUTE_TUPLE_SIZE);
desc->attrs[i]->attnotnull = false;
desc->attrs[i]->atthasdef = false;
}
}
else
desc->attrs = NULL;
desc->constr = NULL;
desc->tdhasoid = tupdesc->tdhasoid;
@ -142,15 +151,18 @@ CreateTupleDescCopyConstr(TupleDesc tupdesc)
desc = (TupleDesc) palloc(sizeof(struct tupleDesc));
desc->natts = tupdesc->natts;
size = desc->natts * sizeof(Form_pg_attribute);
desc->attrs = (Form_pg_attribute *) palloc(size);
for (i = 0; i < desc->natts; i++)
if (desc->natts > 0)
{
desc->attrs[i] = (Form_pg_attribute) palloc(ATTRIBUTE_TUPLE_SIZE);
memcpy(desc->attrs[i],
tupdesc->attrs[i],
ATTRIBUTE_TUPLE_SIZE);
size = desc->natts * sizeof(Form_pg_attribute);
desc->attrs = (Form_pg_attribute *) palloc(size);
for (i = 0; i < desc->natts; i++)
{
desc->attrs[i] = (Form_pg_attribute) palloc(ATTRIBUTE_TUPLE_SIZE);
memcpy(desc->attrs[i], tupdesc->attrs[i], ATTRIBUTE_TUPLE_SIZE);
}
}
else
desc->attrs = NULL;
if (constr)
{
TupleConstr *cpy = (TupleConstr *) palloc(sizeof(TupleConstr));
@ -197,7 +209,8 @@ FreeTupleDesc(TupleDesc tupdesc)
for (i = 0; i < tupdesc->natts; i++)
pfree(tupdesc->attrs[i]);
pfree(tupdesc->attrs);
if (tupdesc->attrs)
pfree(tupdesc->attrs);
if (tupdesc->constr)
{
if (tupdesc->constr->num_defval > 0)
@ -228,7 +241,6 @@ FreeTupleDesc(TupleDesc tupdesc)
}
pfree(tupdesc);
}
/*
@ -361,6 +373,7 @@ TupleDescInitEntry(TupleDesc desc,
*/
AssertArg(PointerIsValid(desc));
AssertArg(attributeNumber >= 1);
AssertArg(attributeNumber <= desc->natts);
/*
* attributeName's are sometimes NULL, from resdom's. I don't know