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    copied!<p>To make this work, I had to add more fluent mappings, to explicitly create the optional mapping of the <code>TransferItem</code> on the <code>Transfer</code> class, as well as make the FK nullable on the <code>TransferItem</code>.</p> <p>I didn't have a problem wrapping this all in a single TransactionScope, once the mappings were fixed.</p> <p>Here's the entire console app:</p> <pre><code> public class Transfer { public long Id { get; set; } public long TransferIncomeItemId { get; set; } public long TransferExpenseItemId { get; set; } public TransferItem TransferIncomeItem { get; set; } public TransferItem TransferExpenseItem { get; set; } } public class Operation { public long Id { get; set; } public decimal Sum { get; set; } } public class TransferItem : Operation { public long? TransferId { get; set; } public Transfer Transfer { get; set; } } public class Model : DbContext { public DbSet&lt;Transfer&gt; Transfers { get; set; } public DbSet&lt;Operation&gt; Operations { get; set; } public DbSet&lt;TransferItem&gt; TransferItems { get; set; } protected override void OnModelCreating( DbModelBuilder modelBuilder ) { modelBuilder.Entity&lt;Transfer&gt;() .HasRequired( t =&gt; t.TransferIncomeItem ) .WithMany() .HasForeignKey( x =&gt; x.TransferIncomeItemId ) .WillCascadeOnDelete( false ); modelBuilder.Entity&lt;Transfer&gt;() .HasRequired( t =&gt; t.TransferExpenseItem ) .WithMany() .HasForeignKey( x =&gt; x.TransferExpenseItemId ) .WillCascadeOnDelete( false ); modelBuilder.Entity&lt;TransferItem&gt;() .HasOptional( t =&gt; t.Transfer ) .WithMany() .HasForeignKey( ti =&gt; ti.TransferId ); } } class Program { static void Main( string[] args ) { using( var scope = new TransactionScope() ) { var context = new Model(); var ti1 = new TransferItem(); var ti2 = new TransferItem(); //deal with the types with nullable FKs first context.Operations.Add( ti1 ); context.Operations.Add( ti2 ); var t = new Transfer(); context.Transfers.Add( t ); t.TransferIncomeItem = ti1; t.TransferExpenseItem = ti2; //save, so all objects get assigned their Ids context.SaveChanges(); //set up the "optional" half of the relationship ti1.Transfer = t; ti2.Transfer = t; context.SaveChanges(); scope.Complete(); } } } </code></pre> <p>When ran produced this database:</p> <p><img src="https://i.stack.imgur.com/HDJR7.png" alt="enter image description here"></p> <p>And this output:</p> <p><img src="https://i.stack.imgur.com/T0OxF.png" alt="enter image description here"></p>
 

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