A transaction must be:

1. Atomic - it is one unit of work and does not dependent on previous and following transactions.

2. Consistent - data is either committed or roll back, no “in-between” case where something has been updated and something hasn’t.

3. Isolated - no transaction sees the intermediate results of the current transaction).

4. Durable - the values persist if the data had been committed even if the system crashes right after.