linq - Best way to get records from linked table

Question

I'm new to entity framework and i have following database structure.

i'm trying to get relevant template for test.

what i have tried so far is as follows:

var val = context.TeamTest
     .Where(x => x.Tests_Id == 47)
     .Select(x => x.Team.Profile.ProfileSelections);

Q1 : why can't i get .Select(x => x.Team.Profile.ProfileSelections.Templates);

I tried this way as well.

List<TeamTaskTemplate> templates = (from candidate in context.TeamTest
                                    join team in context.Teams  
                                    on candidate.Team_ID equals team.Team_ID
                                    join profile in context.Profiles
                                    on team.TeamTaskProfileID equals profile.TeamTaskProfileID
                                    join selectProf in context.ProfileSelections
                                    on profile.TeamTaskProfileID equals selectProf.TeamTaskProfileID
                                    join templ in context.Templates 
                                    on selectProf.TeamTaskTemplateID equals templ.TeamTaskTemplateID
                                    where candidate.Test_Id == 47
                                    select templ).ToList();

Q2 : What is the best way to get records from above 2 methods ?

Q3 in general what is the best way to get records ? ( directly using context object as i mention 1 or use join queries mentioned in 2 ?

Answer 1

Q1: You should switch on LazyLoading:

context.Configuration.LazyLoadingEnabled = true;

And check that Team, Profile, ProfileSelections and Templates properties have virtual annotation.

Q2, Q3: First method is very simple and clear for understanding, but second one can be more effective.

Answer 2

Q1 If you mapping be correctly Info

var val = context.TeamTest.Include("Team.Profile.ProfileSelection.Template")
     .Where(x => x.Tests_Id == 47).ToList();

For me this is the best way because get and set only the data that you needs

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