iqueryable

If the IQueryable interface performs the query expression in the server rather than fetching all records like IEnumerable , why is IQueryable not replaced by IEnumerable where it can be faster and more efficient? DBSet<T> has two flavors of Where ( IQueryable and IEnumerable ). Is there a way to call the IEnumerable version because the IQueryable is called by default, without calling ToList() ? If the IQueryable perform the query Expression in the server rather than fetching all records like IEnumerable , why IQueryable not replaced by IEnumerable where it can be faster and more efficient?

In my code I'd like to make my repositories IQueryable. This way, the criteria for selection will be a linq expression tree. Now if I want to mock my repository in theorie this is very easy : just implement the interface of my repository (which is also a IQueryable object). My mock repository implementation would be only a in memory collection, but my question is : Do you know an easy way to implement the IQueryable interface of my mock, to transfer the query to my in-memory collection (IEnumerable) ? Thanks for your response, Some precision The client object of my repository will use my

I have a class Something that implements ISomething . How can I convert/cast from an IQueryable<Something> to an IQueryable<ISomething> . When I try to cast, I am able to compile, but the result of the cast is always NULL. Background: The reason I am doing this is because my Something class is a CodeSmith-generated class (PLINQO template) that has table mapping decoration, methods, etc. My ISomething interface is "POCO-style", in that it is dumb and simply mirrors the properties of the Something class. It also exists in it's own namespace. I am doing this so I don't have to reference the

I have a database table like this: Entity --------------------- ID int PK ParentID int FK Code varchar Text text The ParentID field is a foreign key with another record in the same table (recursive). So the structure represents a Tree. I'm trying to write a method to query this table and get 1 specific Entity based on a path. A path would be a string representing the Code properties of the Entity and the parent Entities. So an example path would be "foo/bar/baz" which means the one specific Entity of which the Code == "baz" , the parent's Code == "bar" and the parent of the parent's Code ==

I have the following query: var list = repositoy.Query<MyClass>.Select(domain => new MyDto() { Id = domain.Id, StringComma = string.Join(",", domain.MyList.Select(y => y.Name)) }); That works great: list.ToList(); But if I try to get the Count I got an exception: list.Count(); Exception NHibernate.Hql.Ast.ANTLR.QuerySyntaxException A recognition error occurred. [.Count[MyDto](.Select[MyClass,MyDto](NHibernate.Linq.NhQueryable`1[MyClass], Quote((domain, ) => (new MyDto()domain.Iddomain.Name.Join(p1, .Select[MyListClass,System.String](domain.MyList, (y, ) => (y.Name), ), ))), ), )] Any idea how

I have a LINQ query that returns all absences for an employee. The first part of the linq statement gets a basic list of the employees details, but I also return an IQueryable list of illnesses related to that absence. I'd like to somehow convert that IQueryable list to a comma delimited list of Illnesses. Currently I use (majorly stripped down): DetailsOfSickness = ( from t2 in Illnesses join ai1 in AbsenceIllnesses on t2.IllnessID equals ai1.IllnessID select new { Illness = ", " + t2.IllnessName }) Which returns the list but I'd like the results like: Headache, Flu, Cramps.... etc. Any ideas