xw19 Published on: 2018-11-07
ACID stands for Atomicity, Consistency, Isolation and Durability. It is a set of properties that guarantee validity of data in Database systems. In order to understand ACID we need to understand another concept of Transaction. So what is transaction ?
If you want to move some money from one bank account into another bank account. There should be two steps one is deduct from one bank account and then second step is to add the amount to another bank account. Both of these steps together is called as Transaction. So, a collection of operation which perform a single logical operation is called as transaction.
Atomicity: All of the operations of the transaction should happen or non at all. In the bank example it cannot happen that money is deducted but not credited to another account.
Consistency: Data should be valid before and after each of the Transactions
Isolation: Each of the transactions should be independent of one another.
Durability: Once a transaction is performed the data is written into the Database system should persist even if there is a system failure.