ACID RDBMS

Atomicity: In a sequence of steps either all actions occur or none.

Example: Moving money from savings to checking accounts.

Consistency: The database is transformed from one valid state to another valid state.

Example: If someone moves 10,000$ from their checking account that information is logged. If it can't be logged then the money is not transferred.

Isolation: The results of a transaction are invisible to other transactions until the transaction is complete.

Example: If someone an accountant starts a report at 1700 and Joe User deposits 100$ into their account at 1701. The report, even if it finishes at 1702 will not show the changes made by Joe User.

Durability: Once committed (completed), the results of a transaction are permanent and survive future system and media failures.

Example: Once your seat is reserved on an airplane, even if the system crashes the moment it finishes writing that information in the database your seat will still be reserved.