​Distributed Database Management System (DDBMS) Architecture: Standardization, Models, Alternatives; Distributed Database Design: Strategies, Design issues, Fragmentation, Allocation; Distributed Query Processing; Distributed Database Interoperability: Distributed database heterogeneity, schema translation, global schema construction, global and local query processing; Distributed Transaction Management; Distributed DBMS concurrency control; Distributed DBMS recovery and reliability.​