C# NHibernate多对多，无法删除行

我有以下实体：Project、ProjectMapping和User，这是许多映射：

public ProjectMembershipMapping()
{
    Property(pm => pm.IsAccepted, prop => prop.NotNullable(true));
    Property(pm => pm.Permission, prop => prop.NotNullable(true));
    ManyToOne(pm => pm.Member, mapping =>
                                   {
                                       mapping.Lazy(LazyRelation.NoLazy);
                                       mapping.Cascade(Cascade.All);
                                   });
    ManyToOne(pm => pm.Project, mapping =>
                                    {
                                        mapping.Lazy(LazyRelation.NoLazy);
                                        mapping.Cascade(Cascade.All);
                                    }); 

    ComposedId(pm =>                                          
                   {
                       pm.ManyToOne(prop => prop.Member);
                       pm.ManyToOne(prop => prop.Project);
                   });
}

public ProjectMapping()
{   
    Set(proj => proj.Members,
            mapping =>
            {
                mapping.Lazy(CollectionLazy.NoLazy);
                mapping.Inverse(false);
                mapping.Cascade(Cascade.All);
                mapping.Table("ProjectMembership");
                mapping.Key(k => k.Column("Project"));
            },
            action => action.OneToMany()
        );      
}

public class DevcoopUserMapping : ClassMapping<DevcoopUser>
{
        Bag(user => user.ProjectMemberships, 
            mapping =>
                {
                    mapping.Lazy(CollectionLazy.NoLazy);
                    mapping.Inverse(false);
                    mapping.Cascade(Cascade.All);
                    mapping.Table("ProjectMembership");
                    mapping.Key(k => k.Column("Member"));
                },
            action => action.OneToMany());
}

另一方面，当我第一次尝试从Project和User中删除此ProjectMembership实例时（我按照建议从关联中删除它），我得到了异常：

could not delete collection: [devcoop.Daos.Project.Members#1][SQL: UPDATE ProjectMembership SET Project = null WHERE Project = @p0]

---

有人能帮忙吗？应该是我把映射搞砸了，但我不知道这会是什么。

在删除ProjectMembership实例之前，请将其从DevcoopUser.ProjectMemberships和Project.Members-collections中删除

我认为这应该是可行的：

  membership.Member.ProjectMemberships.Remove(membership);
  membership.Project.Members.remove(membership);
  session.Delete(membership);

---

我认为您应该从ProjectMembership映射中删除CascadeAll。我不完全确定，但我认为这会将删除级联到使用CascadeAll映射的集合中的所有成员和项目，这可能是您不希望发生的。

问题在于我现在得到的这些映射导致异常：无法删除集合：[devcoop.Daos.Project.members#1][SQL:UPDATE-ProjectMembership-SET-Project=null，其中Project=@p0]正如我在问题中所写的。在尝试删除ProjectMembership实例之前是否保存用户和项目实体？如果是这样，请尝试在保存用户和项目之前删除ProjectMembership。我不明白NH为什么尝试更新ProjectMembership表。我仅通过在3中使用hql查询成功删除项目交易，嗯，这是一个混乱的解决办法，不是一个解决方案。在NHibernate中有关于多对多的“最佳实践”吗？因为我显然在这些映射上搞砸了什么，但我找不到确切的方法

  membership.Member.ProjectMemberships.Remove(membership);
  membership.Project.Members.remove(membership);
  session.Delete(membership);