1. A method of implementing behavior of a user defined type in a database management system comprising: providing a database on a computer, said database having multiple data tables each with multiple rows; generating within said database a user defined type (UDT) table having only a single row; creating an instance of a UDT having persisted objects; storing said instance of said UDT having said persisted objects within said single row of said UDT table; implementing on said computer a query having a Cartesian product to join said single row UDT table and said multiple data tables; and invoking behavior of said instance of said UDT on said computer to generate multiple resultant data tables without increasing cardinality of each said resultant data table.