User1120430333 posted
The Repository, the Repository pattern, sits behind the Web service.
https://msdn.microsoft.com/en-us/library/ff649690.aspx
The Repository object in the Repository layer can have many responsibilities, and DB access is just one of the responsibilities where the Repository object calls objects in the Data Access Layer to do CRUD operations with the DB.
The Repository object would call Data Access Objects in the DAL to do CRUD with the DB.
http://blog.sapiensworks.com/post/2012/11/01/Repository-vs-DAO.aspx
https://www.tutorialspoint.com/design_pattern/data_access_object_pattern.htm
You don't send datasets with datatables through a Web service.
https://dzone.com/articles/reasons-move-datatables
What you send through the layers and through the Web service is a DTO.
https://en.wikipedia.org/wiki/Data_transfer_object
https://www.codeproject.com/Articles/1050468/Data-Transfer-Object-Design-Pattern-in-Csharp
Like I said, the Repository object is not solely for database access.
