Domain Driven Design: Should Repository methods be passed a configuration string?

Question

I have seen this both ways. When writing a Repository, should the methoods be passed in a connection string or should the repositpry be "self-contained", in other words, know internally how to get to the database? In case it helps, my Repository is not true DDD, but is the Repository pattern surrounding methods that call Oracle SPs (that's the way it is ar work here)?

Answer 1

Repositories should normally not work in their own independent transactional unit, so they most often use the 'existing' database connection. This way you can do multiple repository (database!) operations in a single transaction.

How to implement this depends on your developing platform. Java EE for example has ways to inject the current Entity Manager into objects or ways to get it by code. You can also implement this manually by storing a reference in a thread local storage.