Function transformColumnNameList

src/backend/commands/tablecmds.c:12826–12857

* transformColumnNameList - transform list of column names * * Lookup each name and return its attnum and type OID */

 * Lookup each name and return its attnum and type OID
 */
static int
transformColumnNameList(Oid relId, List *colList,
						int16 *attnums, Oid *atttypids)
{
	ListCell   *l;
	int			attnum;

	attnum = 0;
	foreach(l, colList)
	{
		char	   *attname = strVal(lfirst(l));
		HeapTuple	atttuple;

		atttuple = SearchSysCacheAttName(relId, attname);
		if (!HeapTupleIsValid(atttuple))
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_COLUMN),
					 errmsg("column \"%s\" referenced in foreign key constraint does not exist",
							attname)));
		if (attnum >= INDEX_MAX_KEYS)
			ereport(ERROR,
					(errcode(ERRCODE_TOO_MANY_COLUMNS),
					 errmsg("cannot have more than %d keys in a foreign key",
							INDEX_MAX_KEYS)));
		attnums[attnum] = ((Form_pg_attribute) GETSTRUCT(atttuple))->attnum;
		atttypids[attnum] = ((Form_pg_attribute) GETSTRUCT(atttuple))->atttypid;
		ReleaseSysCache(atttuple);
		attnum++;
	}

	return attnum;
}

/*
 * transformFkeyGetPrimaryKey -