1. A method of combining properties and methods from a plurality of different database systems, the method comprising: executing a first broker service to interact with a first data source using a first protocol to generate a first business object, the first business object including a first property and a first method wherein the first property and the first method define the first business object, the first business object being in a declarative format; executing a second broker service to interact with a second data source using a second protocol to generate a second business object, the first protocol being different than the second protocol, the second business object including a second property and a second method wherein the second property and the second method define the second business object, the second business object being in the declarative format; executing an object broker process to generate a first combined business object that includes the first property, the first method, the second property and the second method, wherein the first property, the first method, the second property and the second method define the first combined business object, the object broker process using the first broker service and the second broker service; storing the first combined business object, the first combined business object being in the declarative format accessing the first combined business object through a form; adding additional data to the first combined business object through the form, and if the additional data cannot be stored in the first data source or the second data source, adding an add-on data source to the plurality of different database systems, the add-on data source including properties and methods, and storing the additional data in the add-on data source; executing an object broker process to generate a second combined business object that includes the first property, the first method, the second property, the second method, and at least one property or method from the add-on data source, wherein the first property, the first method, the second property, the second method and the at least one property or method from the add-on data source define the second combined business object, the object broker process using the first broker service and the second broker service; and storing the second combined business object, the second combined business object being in the declarative format.