ACID model is based on 4 characteristics.
Atomicity: As per Atomicity characteristics, the database modifications must follow an all or nothing rule. If any part of the transaction fails, then entire transaction fails.
Consistency: Consistency states that only valid data will be written to the database. Due to some reason, a transaction is executed that violates the databases consistency rules then the whole transaction will be rolled back.
Isolation: Isolation requires that multiple transactions occurring at the same time not impact each others execution. For example, user Joe withdraws $200 and user Sam withdraws $500 from user Bob account, which has a balance of $1000. Since both Joe and Sam draw from Bob’s account, one of the users is required to wait until the other user transaction is completed, avoiding inconsistent data.
NB: Isolation property does not ensure which transaction will execute first
Durability: Durability ensures that there will not be lost any transaction committed to the database.