DISTRIBUTED DATABASES FOR BANKING SYSTEM WITH OPTIMISTIC LOCKING CONCURRENCY CONTROL

Abstract

In recent years the availability of databases and of computer networks has given rise to a new field: distributed databases. A distributed database system is one in which the database is spread among several sites and application programs move from site to site to access and update the data they need. The concurrency control is that portion of the system that responds to the read and write requests of the application programs. The task of concurrency control algorithm is to ensure the consistency. of the database while allowing a set of transactions to execute concurrently. The organization which ,has branches at different geographical locations cannot. ignore the importance of the distributed database management systems (DDBMS). For example a banking. system having branches at different cities can have its own distributed database system to respond to the need of information of a branch from any other branch and to allow the customers of that bank to perform any banking operations in their accounts at any time and from any geographical location, the.bank has a branch. In this dissertation, we developed and implemented a distributed database system for a computerized banking, a communication protocol, a model for automatic fund machine and a secure accessing strategy to that machine. To make the system more realistic, we implemented for it an optimistic locking technique of concurrency control to prevent the violation of the database consistency if several update requests are processed concurrently in the database system.