1. A computer-implemented method of serving data between a database and a client application, wherein said database comprises data of a native data type which is arranged in a data structure, said method comprising the steps of: examining said database; generating a default schema, wherein the default schema comprises mapping data for converting said data of said native data type to a predetermined data type of a common data model, and wherein said default schema provides a plurality of representations of the data structure of the database; displaying the generated default schema and the data of the native data type graphically; adding an annotation to the default schema, wherein said annotation comprises a child element that identifies the database; mapping at least one of a first element and a first attribute of the default schema to at least a respective one of a second element and a second attribute of a predetermined schema, wherein the mapping is responsive to a mapping instruction, and wherein said predetermined schema includes an annotation copied from the annotation of the default schema; using a computer to create a server application to use said predetermined schema to convert said data of said native data type to data of said predetermined data type; parsing, according to said server application, a query according to the common data model; mapping said parsed query, using said server application, to form a data request of the data of said native data type to be sent to the database; retrieving a required portion of the data from said database in response to said received query; converting said response data according to said server application to form a response to said query according to said common data model; and returning said response to said client application.