Isolation level

Transactional Integrity

ACID Properties

1. Atomic: A transaction must be all or nothing, no partial transaction. Each transaction is a complete unit of work. The entire transaction is either successes or fails no partial transaction.

2. Consistent:  Each transaction preserves database consistency. The database goes from one consistent state to another consistent state.

3. Isolation: Each transaction is separate, means the worked done by transaction A should not affect transaction B.

4.  Durable: Each transaction should be permanent, Means once transaction commit, is always be there.

Transactional Trouble:

1.       Dirty Read

2.       Non Repeatable read

      3.  Phantom rows

Dirty Read : In case of dirty read you will see the modified data by session one even session1 not committed the transaction.

Non Repeatable read: In this Case you can see the different data in same transaction. 

Phantom row : In this case the row inserted by session1 or updated by session one will get visible in session2 even that session started before inserting this row and not yet committed