ACID Properties

Atomicity

The entire transaction takes place at once or it does not happen at all. There is no in between.

Consistency

The database must be in consistent state before and after the transactions. The transaction should not change the consistent state of the database.

Isolation

A transaction that executes separately from another transaction should not interfere.

Durability

If the transaction is committed it should be there no matter what. Even if there is a power failure, windows crash, file system corruption etc.