1 MAKING ORACLE 7 , SYBASE , AND ADABAS D INTEROPERABLE THROUGH CORBA : MIND PROJECT

METU Interoperable DBMS (MIND) is a multidatabase system which aims at achieving interoperability among heterogeneous, federated DBMSs. The architecture of MIND is based on OMG distributed object management model. It is implemented on top of a CORBA compliant ORB, namely, ObjectBroker . In MIND all local databases are encapsulated in a generic database object. The interface of the generic database object is defined in CORBA IDL and multiple implementations of this interface, one for each component DBMSs, namely, Oracle7 , Sybase , Adabas D and MOOD (METU Object-Oriented Database System) (Asuman Dogac, 1994a-b) are provided. MIND provides its users a common data model and a single global query language based on SQL. The main components of MIND are a global query manager, a global transaction manager, a schema integrator, interfaces to supported database systems and a graphical user interface. The integration of export schemas is currently performed by using an object definition language (ODL) which is based on OMG's interface definition language. It is the responsibility of the DBA to build the integrated schema as a view over export schemas. The functionalities of ODL allow selection and restructuring of schema elements from existing local schemas. MIND global query optimizer aims at maximizing the parallel execution of the intersite operations of the global subqueries. Through MIND global transaction manager, the serializable execution of the global transactions (both nested and flat) is provided.