Showing posts with label ACID. Show all posts
Showing posts with label ACID. Show all posts

Sunday, April 25, 2010

Basic transaction concepts

This is mostly referred as "ACID" properties.

So, what are they?

  • Atomicity - When Two or more transactions are taking place, either all of them are committed or none of them are committed.

  • Consistency - That is, after a transaction, valid and new data exists in the database or the data returned to its original state. ROLLBACK function provides the facility of returning data to its original state.
  • Isolation – During a transaction, data must be in an isolated level there by not allowing other transactions to access it.
  • Durability - Data is still available even if the server fails. This is achieved by CHECKPOINTS and DATABASE RECOVERY PROECESS.