Alternative for MapHierarchy() in EF Code first CTP 5

How can I set the following in the new CTP?

modelBuilder.Entity<RequestBase>()
                .MapHierarchy()
                .Case<RequestBase>(b => new { b.Id, b.Comment, Discriminator = 0 })
                .Case<Request1>(s => new { request1_Id = Column.Id,  Discriminator = 1 })
             开发者_JAVA技巧   .Case<Request2>(m => new { request2_Id = Mission.Id, m.Comment, m.Date, Discriminator = 2 })
                .ToTable("dbo.Requests");

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Something like this will work:

modelBuilder.Entity<RequestBase>()
            .Map<RequestBase>(r => r.Requires("Discriminator").HasValue(0))
            .Map<Request1>(r1 => r1.Requires("Discriminator").HasValue(1))
            .Map<Request2>(r2 => r2.Requires("Discriminator").HasValue(2))
            .ToTable("dbo.Requests");