1. A method for accessing customized tables in a database of a computer application, comprising: adding a customized table for storing data to the database, the customized table requiring special functionality; registering a data class associated with the customized table in a custom table directory; defining the data class, the data class to interface between a tool of the computer application associated with a tool class and the customized table in the database, wherein the defined data class is associated with the tool class and the data class defines functionality implemented by a method related to the defined data class and provides the tool access to data in the database, and the tool class defines the specialized functionality required for the customized table, the specialized functionality identified with a code associated with the tool class; defining new methods within the data class to interface between a tool class and the customized table; registering the customized table and the defined data class in the customized table directory by associating the defined data class with the customized table; instantiating a tool from the tool class to operate on data, the tool accessing customized table directory to retrieve the data classes associated with the tool class; and responsive to a request for data from the tool, invoking the newly defined method providing functionality associated with the retrieved data classes and the request to access data stored in the customized table, wherein the computer application is a human capital management application and a terminal receives inputs related to the stored data.