28 June, 2009

Explain ACID properties of the database?

All Database systems which include transaction support implement ACID properties to ensure the integrity of the database. ACID stands for Atomicity, Consistency, Isolation and Durability

  • Atomicity: Each transaction is said to be “atomic.” If one part of the transaction fails, the entire transaction fails. Modifications on the data in the database either fail or succeed.
  • Consistency: This property ensures that only valid data will be written to the database. If, for some reason, a transaction is executed that violates the database’s consistency rules, the entire transaction will be rolled back and the database will be restored to a state consistent with those rules.
  • Isolation: It requires that multiple transactions occurring at the same time not impact each other’s execution.
  • Durability: It ensures that any transaction committed to the database will not be lost.

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