Architecture Patterns with Python

Unit of Work Pattern Recap The Unit of Work pattern is an abstraction around data integrity It helps to enforce the consistency of our domain model, and improves performance, by letting us perform a single flush operation at the end of an operation. It works closely with the Repository and Service Layer patterns The Unit of Work pattern completes our abstractions over data access by representing atomic updates. Each of our service-layer use cases runs in a single unit of work that succeeds or fails as a block. This is a lovely case for a context manager Context managers are an idiomatic way of defining scope in Python. We can use a context manager to automatically roll back our work at the end of a request, which means the system is safe by default. SQLAlchemy already implements this pattern We introduce an even simpler abstraction over the SQLAlchemy Session object in order to “narrow” the interface between the ORM and our code. This helps to keep us loosely coupled.