Repository pattern has been around for long time but suffers through some issues. General nature of its implementation comes in the way of extending repository pattern to use it with complex domain models involving large number of entities. Repository contract can be limiting and confusing when there is a need to write complex and very specific queries. Trying to fix these issues with repositories may result in leaky abstraction which can bite us later. Moreover, repositories maintained with less care have a tendency to grow into god objects and maintaining them beyond that point becomes a challenge.

Specification pattern and query object pattern solve these issues on the read side of the things. Different applications have different data access requirements. Some applications are write-heavy while others are read-heavy. But there are a minute number of applications that fit into former category. A large number of applications developed these days are read-heavy. I have worked on...