database transaction.md

db transaction is a single unit of work that are often made up of multiple db operations.

Following five operations composes one db transaction.

1. create a transaction record of 10 EUR from account1 to account2
2. create an entry record of -10 EUR for account1
3. create an entry record of 10 EUR for account2
4. reduce account1's amount by -10 in their account record
5. increase account2's amount by 10 in their account record

db transaction must be [[ACID]]