具有私有支持字段的 nhibernate 集合查询
我在学生和教授 (_students_selected) 之间的数据库（带有桥接表）中建模了一对多关系，在我的实体中，我将其建模为一对多关系，即教授有一个学生。
HasManyToMany<Student>(Reveal.Member<Professor>("_students"))
.Table("_students_selected").ChildKeyColumn("student_key").ParentKeyColumn("professor_key");
public class Professor
{
private IList<Students> _students;
public virtual Student Student
{
get { return _students.FirstOrDefault(); }
}
}
上面的方法在获取数据时有效，但是在查询教授时，我无法添加学生的 where 条件，因为实际数据映射到私人支持字段 _students。我该如何查询这个？下面的代码不起作用。
_unitOfWork.Session.QueryOver<Professor>().Where(i => i.Student.Id == 24).List();
I have a mant-to-many relationship modeled in the database (with a bridge table) between Student and Professor (_students_selected) , in my entites i have modeled it as a one-to-many relationship i.e. a Professor has one Student.
HasManyToMany<Student>(Reveal.Member<Professor>("_students"))
.Table("_students_selected").ChildKeyColumn("student_key").ParentKeyColumn("professor_key");
public class Professor
{
private IList<Students> _students;
public virtual Student Student
{
get { return _students.FirstOrDefault(); }
}
}
The above works when getting the data however when querying over the Professors i am unable to add a where condition on the students because the actual data is mapped to the private backing field _students. How do i query this? code below does not work.
_unitOfWork.Session.QueryOver<Professor>().Where(i => i.Student.Id == 24).List();
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NHibernate 无法将属性内的 C# 代码转换为 SQL，它只能使用映射的属性。要么在语句中使用集合（当然需要是公共/内部的），要么过滤内存中的结果（但要小心 select n + 1 问题）。
NHibernate can't translate your C# code inside the property to SQL, it can only work with mapped properties. Either use the collection in the statement (which needs to be public/internal then of course) or filter the results in memory (but be careful with select n + 1 problems then).