1. A relational database management system of the type wherein a table function returns a set of result rows which are represented in an SQL statement by a container for the table function, the relational database management system having the improvement comprising: a rewrite method associated with the table function that returns an SQL string that when executed will return an equivalent set of result rows, the relational database system executing the rewrite method prior to executing the container to obtain the SQL string and thereupon rewriting the SQL statement such that the container for the table function is replaced by the returned SQL string.