Should a Repository return IEnumerable , IQueryable or List?

Question

I\'d like to make my application as flexible as possible, but not dig myself into a hole by making my Interface too specific.

What is the best object

Answer 1

It depends on whether you wish to have any future queries performed on the entity and whether these should be in memory or not:

• If there are to be future queries and the DB should do the work return IQueryable.
• If there are to be future queries and it is to be done in memory return IEnumerable.
• If there are to be no further queries and all the data will need to be read return an IList, ICollection etc.