What are the types of serializability?Transaction serializabilityConceptual serializabilityView serializabilityConflict serializability

Serializability is a concept in database systems that ensures the consistency of a database in a concurrent environment. There are several types of serializability:

1. Transaction Serializability: This is the basic form of serializability where transactions are executed one after the other. It ensures that the outcome of a set of transactions is the same as if the transactions were executed serially.

2. Conceptual Serializability: This is a higher level of serializability that deals with the concept of a transaction rather than the specific operations within it. It ensures that the overall effect of executing a set of transactions is the same as if they were executed in some serial order.

3. View Serializability: This is a type of serializability where the order of uncommitted transactions does not affect the final result. It ensures that the view of the database remains the same even if transactions are executed in a different order.

4. Conflict Serializability: This is a type of serializability that deals with conflicts between transactions. It ensures that the order of conflicting operations in a set of transactions is the same as if the transactions were executed in some serial order.

Serializability is a property of a schedule of transactions. It ensures that the concurrent execution of the transactions leads to a result that could be obtained by executing the transactions one after the other in some order. There are several types of serializability:

1. Transaction Serializability: This is the basic form of serializability where transactions are ordered in a way that is equivalent to their serial execution. This means that if we have transactions T1 and T2, the result of executing T1 before T2 is the same as executing T2 before T1.

2. Conceptual Serializability: This is a more abstract form of serializability. It is not concerned with the actual order of execution of the transactions, but rather with the conceptual result. If the final state of the database after executing all transactions is the same as it would be in some serial execution of the transactions, then the schedule is conceptually serializable.

3. View Serializability: This is a relaxation of conflict serializability. A schedule is view serializable if it is view equivalent to a serial schedule. Two schedules are view equivalent if the same set of initial reads, final writes and updates (write followed by read) of transactions occur in both schedules.

4. Conflict Serializability: This is a stricter form of serializability. A schedule is conflict serializable if it can be transformed into a serial schedule by swapping non-conflicting operations. Two operations are said to be conflicting if they belong to different transactions, operate on the same data item, and at least one of them is a write operation.