Tuesday, 29 March 2016

ACID Properties

Atomicity :
 Ensures that all operations with in the work unit are completed successfully , otherwise the transaction is aborted at the point of failure and previous operations are rolled back to their original state.

Consistency:
 ensures that the database properly changes states upon a successfully committed transactions.

Isolation:
 Enables transactions to operate independently and transparent to each other.

Durability:
 Ensures that result or effect of a committed transaction persist in case of system failure.


Transaction control:

1. Commit : to save the changes.
2. Rollback : to rollback the changes.
3. Savepoint : creates points with in groups of transactions in which to case to rollback.
4. Set transaction: places  name on transaction.

Note:
1. transaction commands can only be used with insert,update and delete. 

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