Question

我无法在任何地方找到它，但它似乎很微不足道。所以，请原谅这是否重复。

我有类似的东西：

public class Doctor : Entity
{
    ...some other properties here...
    public virtual string Email { get; set; }
}

public class Lawyer : Entity
{
    ...some other properties here...
    public virtual string Email { get; set; }
}

我希望在Lawyers表中返回所有没有电子邮件匹配的医生，如：

select * from Doctors d
where d.Email not in
(select l.Email from Lawyers l where l.Email is not null)

或使用联接：

select d.* from Doctors d
left join Lawyers l on l.Email = d.Email
where l.Email is null

问题是电子邮件当然不是设置为外键。我没有映射到Lawyer的Doctor实体的映射属性。

到目前为止我尝试过：

ICriteria criteria = Session.CreateCriteria(typeof(Doctor))
    .CreateAlias("Lawyers.Email", "LawyerEmail", JoinType.LeftOuterJoin)
    .Add(Restrictions.IsNull("LawyerEmail"));

return criteria.List<Doctor>();

但是，我得到了“无法解析MyPlatform.MyNamespace.Doctor的律师”错误。任何想法如何设置我的DoctorMap并调整标准tomfoolery来实现这一目标？

NHibernate的损失........实体框架的胜利......

Answer 1

我们可以通过一个名为子查询的功能实现这一目标：

// a inner SELECT to return all EMAILs from Lawyer table
var subQuery = DetachedCriteria.For<Lawyer>()
    .SetProjection(Projections.Property("Email"));

// the root SELECT to get only these Doctors
var criteria = session.CreateCriteria<Doctor>();

// whos email is not in the sub SELECT
criteria.Add(Subqueries.PropertyNotIn("Email", subQuery));

// get first 10
var result = criteria
    .SetMaxResults(10)
    .SetFirstResult(0) // paging
    .List<Doctor>();

流利的Nhibernate加入非外国关键财产

1 个答案: