SchedulesEven when we are scheduling the transactions, we can have two transactions in parallel, if they are independent. But if they are dependent by any chance, then the results will change. For example, say one transaction is updating the marks of a student in one subject; meanwhile another transaction is calculating the total marks of a same student. If the second transaction is executed after first transaction is complete, then both the transaction will be correct. But what if second transaction runs first? It will have wrong total mark.
In all these cases if the transaction is serialized, then the issues can be resolved.