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Abstract
<b>Distributed database systems (DDBS) are systems that have their data distributed and replicated over several locations; unlike the centralized data base system (CDBS), where one copy of the data is stored. Data may be replicated over a network using horizontal and vertical fragmentation similar to projection and selection operations in Structured Query Language (SQL). Both types of database share the same problems of access control and transaction management, such as user concurrent access control and deadlock detection.
On the other hand, DDBS must also cope with different problems. Access control and transaction management in DDBS require different rules to monitor data retrieval and update to distributed and replicated databases.
Distributed database systems are subject to data inconsistency in the presence of failures. In order to coordinate the execution of the sub transactions of a global transaction, it is necessary to commit or abort all these sub transactions to maintain data consistency. 2PC guarantees the atomicity of distributed transactions, that is, that all cohorts of a transaction either commit or abort the transaction.
The cost of 2PC is an important factor in the performance of distributed transactions. Experimental results demonstrate that the
SUMMARY
Distributed database systems (DDBS) are systems that have their data distributed and replicated over several locations; unlike the centralized data base system (CDBS), where one copy of the data is stored. Data may be replicated over a network using horizontal and vertical fragmentation similar to projection and selection operations in Structured Query Language (SQL). Both types of database share the same problems of access control and transaction management, such as user concurrent access control and deadlock detection.
On the other hand, DDBS must also cope with different problems. Access control and transaction management in DDBS require different rules to monitor data retrieval and update to distributed and replicated databases.
Distributed database systems are subject to data inconsistency in the presence of failures. In order to coordinate the execution of the sub transactions of a global transaction, it is necessary to commit or abort all these sub transactions to maintain data consistency. 2PC guarantees the atomicity of distributed transactions, that is, that all cohorts of a transaction either commit or abort the transaction.
The cost of 2PC is an important factor in the performance of distributed transactions. Experimental results demonstrate that the