Assume a schedule consists of consistent transactions that execute in an isolated fashion except for one transaction that performs a single update that is lost (as in Figure 18.2). Showthat the final state of the database satisfies all integrity constraints but nevertheless is incorrect.

What will be an ideal response?

The values in the final database are the same as if T had never executed. Since all the other transactions are consistent and executed in an isolated fashion, the final database satisfies all integrity constraints. The database might nevertheless be incorrect because the update that was lost might be important for the application, for example as in the schedule of Figure 18.2.