The RankId field is both an FK and a PK, but it is NOT an auto generated field.

I use this code to add row

	var context = new ProjectContext();
    Rank rank = new Rank
    {
		RankId = rankId,
        Vote = vote
    };
    context.Ranks.Add(rank);
    context.SaveChanges();

The error message is: {"Cannot insert the value NULL into column 'RankId', table 'MyProject.dbo.Rank'; column does not allow nulls. INSERT fails.\r\nThe statement has been terminated."}