WillCascadeOnDelete不工作

Question

我有两张桌子

public class ServiceRendering
{
  [DataMember]
  public int Id { get; set; }

  [DataMember]
  public virtual IList<ServiceRenderingProduct> ServiceRenderingProducts { get; set; }
}

public class ServiceRenderingProduct
{
  [ForeignKey("ServiceRendering")]
  [DataMember]
  public int ServiceRenderingId { get; set; }

  [DataMember]
  public virtual ServiceRendering ServiceRendering { get; set; }

  [DataMember]
  public int Id { get; set; }
}

并设定他们之间的关系

modelBuilder.Entity<ServiceRendering>().HasMany(x => x.ServiceRenderingProducts).WithRequired(x => x.ServiceRendering).HasForeignKey(x => x.ServiceRenderingId  ).WillCascadeOnDelete(true);

但是在删除ServiceRenderingEntity时，我没有删除ServiceRenderingProduct实体。我应该在数据库中设置任何约束吗？或者还有其他原因吗？