Serializability and recoverability are usually treated as two orthogonal problems, when in practice, they are closely related to each other. This artificial separation results in correctness criteria that are unnecessarily restrictive. A different approach is considered in the Unified Theory in which recovery is made part of the concurrency control criterion by including all recovery operations as part of the history to be considered. This results in a simplified view of concurrency control and in addition allows more concurrency.

Several theoretical evaluations have been done concerning Unified Theory. In this project an implementation of a concurrency controller using the idea of Unified Theory is proposed and its performance is compared to that of Two-Phase Locking scheduling. Different system loads and transactions are simulated and the advantages of both algorithms are discussed.