Paging params - domain repository interface

Question

I usually define my repository interfaces at Domain Layer with DDD. Given that the UI needs to display some paged data I thought that adding params such as currentPage, pageSize, and define a model PagingResult at my domain layer have not to do with domain itself.

This is the method signature:

PagingResult<Customer> GetCustomers(int currentPage, int pageSize, string nameToFind);

Should I keep this method at my domain ICustomerRepository? I thought about define it on application layer within a new ICustomerAppRepository.

So basically the question is: is it fine or common to have this kind of method on domain repositories interfaces?

Answer 1

Sometimes you just need to support pagination at the database layer, for performance reasons. It's not a violation of separation of concerns if you conceptualize pagination in an application-agnostic way.

So for example instead of

PagingResult<Customer> GetCustomers(int currentPage, int pageSize, string nameToFind);

You could write

IEnumerable<Customer> GetCustomers(string nameToFind, int numberToReturn);

and

IEnumerable<Customer> GetCustomers(
    string nameToFind, 
    int numberToReturn, 
    Customer startAfter
);

You could then use the first method above to get the first set of results and use the second method to get subsequent result sets starting with the first customer after the last row of the previous page.

This removes the concept of pagination from the data layer but still gives you the methods you need to obtain the records for the UI.