What is view equivalence?

Two schedules S and S’ are said to be view equivalent if the following three conditions hold :

1. Both S and S’ contain same set of transactions with same operations in them.

2. If any read operation read(x) reads a value written by a write operation or the original value of x the same conditions must hold in the other schedule for the same read(x) operation.

3. If an operation write1(y) is the last operation to write the value of y in schedule S then the same operation must be the last operation in schedule S’.