Constructing IDL Views on Relational Databases

Data collections are distributed at many different sites and stored in numerous different database management systems. The industry standard CORBA can help to alleviate the technical problems of distribution and diverging data formats. In a CORBA environment, data structures can be represented using the Interface Definition Language IDL. Manually coding a server, which implements the IDL through calls to the underlying database, is tedious. On the other hand, it is in general impossible to automatically generate the CORBA server because the IDL is not only determined by the schema of the database but also by other factors such as performance requirements. We therefore have developed a method for the semi-automatic generation of CORBA wrappers for relational databases. A declarative language is presented, which is used to describe the mapping between relations and IDL constructs. Using a set of such mapping rules, a CORBA server is generated together with the IDL. Additionally, the server is equipped with a query language based on the IDL. We have implemented a prototype of the system.