A novel rules engine which automates many warehouse processes, and provides for efficient management of a warehouse. The rules engine provides a flexible and customizable structure for modeling the many different types of processes governing the function of a warehouse. The rules engine translates business level logic into code for manipulating the warehouse database. The rules engine allows a user to create their own user logic for working with the database, which operates at a level of abstraction more feasible for the user. The rules engine understands the user logic by the way the user decides how to string various restrictions together. The rules engine implements the translation via its internal understanding of the structure of the particular application. Thus, the rules engine allows the user to define logic without understanding how to manipulate a database.