Method and apparatus for performing multi-class object fetch in a database management system

A method and apparatus is provided for populating an object-oriented data structure from data stored in a conventional relational database. In particular, a method and apparatus is provided for transforming the results of a complex relational database query such as a join query (i.e., where each row of results from the relational database corresponds to data from multiple tables) into a network of inter-related heterogeneous objects contained an object-oriented data structure. Further, the present invention provides a method and apparatus for more efficiently knitting the relationships between newly created objects in an object-oriented data structure.