Transaction Boundaries

A transaction boundary defines the scope within which a group of database operations succeeds or fails together.

My current understanding

A transaction should normally correspond to a meaningful application operation rather than an individual repository call.

Consider an operation containing several persistence steps:

$$T = \{O_1, O_2, O_3\}$$

If $O_3$ fails, the application may need $O_1$ and $O_2$ to roll back as part of the same transaction.

Connections

This connects directly to Repository Pattern and the service layer.

Questions

• When should transaction management be declarative?
• How should nested application operations behave?
• Where does Unit of Work fit?