Conflict Equivalence and Conflict Serializable Schedule

Conflict Equivalence :

Schedules are conflict equivalent if they can be transformed one into other by a sequence of non conflicting interchanges adjacent actions.

Conflict Serializable Schedule :

A Schedule is conflict serializable if it is conflict equivalent to any of serial schedule.

View Equivalent Schedule and View serializable schedule

View Equivalent Schedule :

Consider two schedules S1 and S2, they are said to be view equivalent if following conditions are true :

Initial read must be same. There are two transactions say Ti and Tj, The schedule S1 and S2 are view equivalent if in schedule S1, Ti reads A that has been updated by Tj, and in schedule S2, Ti must read A from Tj. i.e. write-read(WR) sequence must be same between S1 and S2. Final write operations should be same between S1 and S2. View serializable schedule :

A Schedule is view serializable if it is view equivalent to any serial schedule. The following two examples will illustrate how to find view equivalent schedule.