Homogeneous Distributed Databases In a homogeneous distributed database All sites have identical software Are aware of each other and agree to cooperate in processing user requests. Each site surrenders part of its autonomy in terms of right to change schemas or software Appears to user as a single system In a heterogeneous distributed database Different sites may use different schemas and software Difference in schema is a major problem for query processing Difference in software is a major problem for transaction processing Sites may not be aware of each other and may provide only limited facilities for cooperation in transaction processing Database System Concepts-6th Edition 19.4 @Silberschatz,Korth and SudarshanDatabase System Concepts - 6 19.4 ©Silberschatz, Korth and Sudarshan th Edition Homogeneous Distributed Databases In a homogeneous distributed database All sites have identical software Are aware of each other and agree to cooperate in processing user requests. Each site surrenders part of its autonomy in terms of right to change schemas or software Appears to user as a single system In a heterogeneous distributed database Different sites may use different schemas and software  Difference in schema is a major problem for query processing  Difference in software is a major problem for transaction processing Sites may not be aware of each other and may provide only limited facilities for cooperation in transaction processing