Function attnameAttNum

src/backend/parser/parse_relation.c:3734–3755

* given relation and att name, return attnum of variable * * Returns InvalidAttrNumber if the attr doesn't exist (or is dropped). * * This should only be used if the relation is already * table_open()'ed. Use the cache version get_attnum() * for access to non-opened relations. */

 *	for access to non-opened relations.
 */
int
attnameAttNum(Relation rd, const char *attname, bool sysColOK)
{
	int			i;

	for (i = 0; i < RelationGetNumberOfAttributes(rd); i++)
	{
		Form_pg_attribute att = TupleDescAttr(rd->rd_att, i);

		if (namestrcmp(&(att->attname), attname) == 0 && !att->attisdropped)
			return i + 1;
	}

	if (sysColOK)
	{
		if ((i = specialAttNum(attname)) != InvalidAttrNumber)
			return i;
	}

	/* on failure */
	return InvalidAttrNumber;
}

/* specialAttNum()
 *