... 1999). An example of this can be seen in the appendices in tests 18 and 19. In a multi-session database system environment, there are usually two primary requirements. First the data must be read and modified in a consistent, predictable manner without the risk of loss or corruption (Elmsari & Navathe, 1994). That is to say, it must be kept in a consistent state. Second, concurrent data access by multiple users must be optimised with the highest possible performance to provide maximum productivity for all users of the system. In this report we will be discussing multi-user issues in databases including transaction management, recovery, locking, time stamping, concurrency control and indexes. 2.0 Transactions Transactions are fundamental to the idea of controlled concurrent access to multi-user systems. A Transaction is a logical unit of a database processing that includes one or more database access operations. The operations may be insertion, deletion, modification ...

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