1. A system for providing access by an add-on application to a server-based application and database associated with the server-based application, comprising: a processor configured with an event sink component object model object connected to an add-on component object model (COM) object, a business management application, and the add-on application, the processor configured to execute instructions: provide a set of C++ programming language classes and interface definitions in a persistency layer of the software architecture; develop a persistent business object in an add-on application using the set of C++ programming language classes and interface definitions; connect the persistent business object to a database through a data interface application programming interface (DI API) and a user application programming interface (UI API) to read data from and write data to the database associated with the server-based application, execute the set of C++ programming language classes to implement the persistent business objects; create a first database request based on a first request for data from the persistent business object by determining a type of the database containing the requested data, wherein the first database request is in a first format, and reformat the first request for data from the persistent business object as the first database request using a structured query language (SQL) based on the type of the database, wherein the first request for data from the persistent business object has a second format; receive a response to the first database request in the second format through the data interface application programming interface (DI API) and the user application programming interface (UI API) at a generic interface; generate a response to the data request in the first format from the response to the database request; and send the response to the data request in the first format to the add-on application, wherein the first format is a non-structured query language format and the second format is a structured query language format; provide template classes enabling starting of the add-on application; register a form from the add-on application; and route an event from the server-based application to the add-on application through the user interface application programming interface (UI API) and the data application programming interface (DI API), wherein the event is at least one of a start of business management application event, a stop of business management application event, a form creation event, a menu event, a business management application administration event, a read event, a write event, an administration event, an application load event or an application unload event.