Attribute Level Locking to Improve Data Availability in a Distributed System

Abstract

Distributed systems consist of a number of computers connected over a network in which numerous users are using such systems locally or via the Internet to meet their requirements. As the system is multiple users’ environment, the lock control is an essential part to control the concurrent accessing on the same data item. This system presents a lockable unit on the attributes of a record. So, the database records increased in accessibility because the attributes are locked instead of the entire row. This technique may allow several transactions to access the database row simultaneously by utilizing some attributes and keeping others available for other transactions. In this thesis, concurrency control is mainly implemented by using attribute level locking with the combination of three phases locking (which contain read lock, write intent lock and write lock) in order to prevent dead lock and to control concurrent processing for employee management system. This system is implemented using C# programming language with Microsoft Visual Studio 2013 and database engine is implemented with Microsoft SQL Server 2008 R2.