A: Atomicity
A transaction must be atomic, i.e. it is either performed entirely or no changes are reflected in the database. Partially capturing the effects of a transaction may lead to further errors.
C: Consistency
All changes made to the database should maintain the consistency of the database.
I: Isolation
Multiple transactions occurring on the same database must remain unaffected by each other.
D: Durable
The transactions that are completed successfully must remain in the database even after any system crash.