EF DbContext. How to avoid caching?

Question

Spent a lot of time, but still cann\'t understand how to avoid caching in DbContext.

I attached below entity model of some easy case to demonstrate what I mean.

Answer 1

You can use the AsNoTracking method on your query.

var res = (from b in ctx.Buildings.Where(x => x.ID == 1)
         select new
         {
            b,
            flats = from f in b.Flats
                    select new
                    {
                       f,
                       people = from p in f.People
                       where p.Archived == false
                       select p
                    }
         }).AsNoTracking().AsEnumerabe().Select(x => x.b).Single();

I also want to note that your AsEnumerable is probably doing more harm than good. If you remove it, the Select(x => x.b) will be translated to SQL. As is, you are selecting everything, then throwing away everything but x.b in memory.

Answer 2

have you tried something like:

ctx.Persons.Where(x => x.Flat.Building.Id == 1 && x.Archived == false);

===== EDIT =====

In this case I think you approach is, imho, really hazardous. Indeed you works on the data loaded by EF to interpret your query rather than on data resulting of the interpretation of your query. If one day EF changes is loading policy (for example with a predictive pre-loading) your approach will "send you in then wall".

For your goal, you will have to eager load the data you need to build your "filterd" entity. That is select the building, then foreach Flat select the non archived persons.

Another solution is to use too separate contexts in an "UnitOfWork" like design.