One big repository vs. many little ones?

Question

I have several product tables in my database:

• ProductTypes
• ProductCategories
• ProductCategoryItems
• ProductInventory

The way I see it now, I can make IProduct which would have methods such as:

• FindAllTypes()
• FindAllCategories(int typeId)
• FindAllItems(int categoryId)

Or, I can separate each to mimic the table structure: IProductType, IProductCategory, etc.

Is there a reason to go with one over another?

Answer 1

The idea of repositories is to delegate each one with responsibility for a single entity. In this case making a repository for each entity is recommended. You can go for the big repository one as well, but is not the best solution. In the end you'll get a HUGE class with lots of methods and really tight coupled. Also difficult to give maintenance to.

Answer 2

I don't think having a huge repository is really a good idea, then you'd basically have a data access god class that does everything.

I like to have a base Repository<T> which does common operations such as GetById and GetAll. I normally have all my repositories inherit this base class to get the common methods for free, so I don't have to keep rewriting the same code.