Serializability

Serializability is the classical concurrency scheme.

• It ensures that a schedule for executing concurrent transactions is equivalent to one that executes the transactions serially in some order.

  • It assumes that all accesses to the database are done using read and write operations.

• A schedule is called "correct" if we can find a serial schedule that is "equivalent'' to it.

Given a set of transactions, two schedules of these transactions are equivalent if the following conditions are satisfied:

• Read-Write Synchronization: If a transaction reads a value written by another transaction in one schedule, then it also does so in the other schedule.

• Write-Write Synchronization: If a transaction overwrites the value of another transaction in one schedule, it also does so in the other schedule.