具有多个表的存储库模式

Question

Recently I have been reading up on using the repository pattern and DI to help create easily testable code, I think I understand it for the most part. However I'm having difficulty with one issue. I need to create a Rules object for my applications business layer. To create a rule, I need the ability to read and write to two tables. How would you go about implementing a repository that uses two tables for one object?

for example:

ICollection<type> GetAllRules();

What would I put in for type as it requires two tables?

Thanks

Steve

Answer 1

I wouldn't insist on having a repository for that.

As Fowler says

Conceptually, a Repository encapsulates the set of objects persisted in a data store and the operations performed over them, providing a more object-oriented view of the persistence layer.

This is probably why most implementations tend to expose pure domain objects rather than derivatives (which your Rule object seems to be).

I would have two repositories for the two tables you mention, then I would have a unit of work to expose all repositories and then I would have a business layer service responsible for the compound processing.

An advantage of such approach would be that the repository layer remains clean, there is no business processing involved here, no unclear rules introduced to the persistence layer.