Question

Just playing around with entity framework.

Now I have a simple database, containing to Entities

Person (Id, Name)
Profession (Id, Designation)

which has an association on the Id.

I want to give a person a new profession programatically with this code:

using (PersonDataModelContainer dmc = new PersonDataModelContainer())
{
    var pers = new Person() { Id = PersonId };
    dmc.Person.Attach(pers);
    var prof = new Profession() { Id = ProfessionId };
    dmc.Profession.Attach(prof);
    pers.Professions.Add(req);

    var result = dmc.SaveChanges();

    return (result > 0);
};

I’m quite new to EF, so it is possibly quite simple.

the effect is: nothing happens and I do not see any
new Association in the associations table.

How can I add a new association from existing entities?

Is there any good documentation on working with that concept?

-edit-
found a copy of the database in the bin\debug folder.
It doesn’t contain associations either. but there seems
to be writes to that file each time I fire the update as
in the code above.

Answer 1

I guess you should to use this SQL Compact, Identity Columns and Entity Framework

            using (var con = new PersonDataModelContainer())
            {
                var pers = new Person() { Id = PersonId };

                int pId = 0;
                if (pers.PersonId > 0)
                {
                    pers = con.Persons.FirstOrDefault(c => c.PersonId == pers.PersonId);
                    pId = pers.pId;
                }
                else
                    pId = con.Users.NextId(c => c.PersonId) + 1;

                if (pers.UserId == 0)
                    con.Persons.AddObject(pers);
                con.SaveChanges();
                pId = Persons.PersonId;


                var prof = new Profession() { Id = ProfessionId, PersonId = pId };

                int profId = 0;
                if (prof.PersonId > 0)
                {
                    prof = con.Professions.FirstOrDefault(c => c.ProfessionId == prof.ProfessionId);
                    profId = prof.PersonId;
                }
                else
                    profId = con.Professions.NextId(c => c.ProfessionId) + 1;

                if (prof.ProfessionId == 0)
                    con.Professions.AddObject(prof);
                con.SaveChanges();
                prof.ProfessionId = profId;
            }