However, although two transactions may be perfectly correct in themselves, the inter-leaving of operations in this way may produce an incorrect result, thus compromising the
integrity and consistency of the database. We examine three examples of potential prob-lems caused by concurrency: the lost update problem , the uncommitted dependency
problem , and the inconsistent analysis problem . To illustrate these problems, we use a
simple bank account relation that contains the DreamHomestaff account balances. In this
context, we are using the transaction as the unit of concurrency control.