ACID stands for Atomicity, Consistency, Isolation, and Durability. It is a set of properties that guarantee the validity of data in Database systems. In order to understand ACID, we need to understand another concept of Transaction. So what is the transaction?
If you want to move some money from one bank account into another bank account. There should be two steps one is deducted from one bank account and the second step is to add the amount to another bank account. Both of these steps together with is called a Transaction. So, a collection of operation which performs a single logical operation is called a transaction.
Atomicity: All of the operations of the transaction should happen or non at all. When we are doing bank transaction. For, a bank the deduction from one account and adding to the other account must happen or the deduction should not happen at all.
Consistency: Data should be valid before and after each of the Transactions
Isolation: Each of the transactions should be independent of one another.
Durability: Durability guarantees that once we have committed one transaction into the database data will remain there even if there is system failure. From the bank example if the teller/accountant has committed some money into your account and at that moment there is power failure the data should still remain on the bank’s computer.