Question

I tried following code with following designed model.
First call to SaveChanges() is succeed but not when it comes to second call.

I have already worked 18 hours on this and can’t figure out what is the problem.
Specially when I can achieve the code goal manually with MSSQL server explorer !

Can anyone provide me a solution ?

        var mc = new Model1Container1();

        mc.Categories.Add(new Category() { Text = "Laptop" });
        mc.Categories.Add(new Category() { Text = "TV" });
        mc.SaveChanges();

        var cat = mc.Categories.Where(c => c.Text == "Laptop").FirstOrDefault();
        CKey ck = new CKey() { Key = "RAM" };
        cat.CKeys.Add(ck);

        for (int i = 1; i < 100; i++)
        {
            var ia = new Item() { Text = "MSI GX780-R", Category = cat };

            ia.CProperties.Add(new CProperty() { Value = "4GB", CKey = ck });

            mc.Items.Add(ia);
            mc.SaveChanges();
        }

Answer 1

You are trying to associate the same CKey instance to 100 instances of CProperty, but according to the graph of multiplicities, a given instance of CKey can only be associated to at most 1 CProperty.

Either create a new instance of CKey in each iteration of the loop, or modify your schema.