Function get_attnum

src/backend/utils/cache/lsyscache.c:1005–1022

* get_attnum * * Given the relation id and the attribute name, * return the "attnum" field from the attribute relation. * * Returns InvalidAttrNumber if the attr doesn't exist (or is dropped). */

 *		Returns InvalidAttrNumber if the attr doesn't exist (or is dropped).
 */
AttrNumber
get_attnum(Oid relid, const char *attname)
{
	HeapTuple	tp;

	tp = SearchSysCacheAttName(relid, attname);
	if (HeapTupleIsValid(tp))
	{
		Form_pg_attribute att_tup = (Form_pg_attribute) GETSTRUCT(tp);
		AttrNumber	result;

		result = att_tup->attnum;
		ReleaseSysCache(tp);
		return result;
	}
	else
		return InvalidAttrNumber;
}

/*
 * get_attstattarget