Nhibernate 按Id将实体映射到自联接表

我的旧表AllData有以下列：Id、标题、LookupColumn1Id 我的实体：

public class BaseEntity
{ 
    public virtual int Id { get; set; }
    public virtual string Name { get; set; }
}
public class Employee: BaseEntity
{ 
    public virtual int DepartmentId { get; set; }
    public virtual string DepartmentName { get; set; }
}
public class Department: BaseEntity
{
    public virtual int HeadManagerId { get; set; }
}

我想生成如下选择：

SELECT EmployeeTable.Title, DepartmentTable.Id, DepartmentTable.Title
FROM AllData EmployeeTable left outer join AllData DepartmentTable on EmployeeTable.LookupColumn1Id=DepartmentTable.Id       
WHERE EmployeeTable.tp_ListId = @p0 and (DepartmentTable.Title = @p1)       

public class BaseEntity
{
    public virtual int Id { get; set; }
    public virtual string Name { get; set; } 
}
public class Employee : BaseEntity
{
    public virtual Department Department { get; set; } // to lookup record
}
public class Department : BaseEntity
{
    public virtual IList<Employee> Employees { get; set; } // the way back 
}

<class name="Department" table="[dbo].[AllData]" lazy="true" batch-size="25" 
    where="LookupColumn1Id IS NULL" >
  <id name="Id" column="Id" generator="native" />

  <property not-null="true"  name="Name" column="Title" />

  <bag name="Employees" >
    <key column="LookupColumn1Id" />
    <one-to-many class="Employee"/>
  </bag>

</class>

<class name="Employee1" table="[dbo].[AllData]" lazy="true" batch-size="25"
  where="LookupColumn1Id IS NOT NULL" >
  <id name="Id" column="Id" generator="native" />

  <property not-null="true"  name="Name" column="Title" />

  <many-to-one name="Department" class="Department" column="LookupColumn1Id " />
</class>

---

让我给你看看，其中一个选择。对于这个草案，我希望那些确实具有LookupColumn1Id为NULL的记录将扮演部门的角色，其余的将扮演员工的角色

实体可以如下所示：

SELECT EmployeeTable.Title, DepartmentTable.Id, DepartmentTable.Title
FROM AllData EmployeeTable left outer join AllData DepartmentTable on EmployeeTable.LookupColumn1Id=DepartmentTable.Id       
WHERE EmployeeTable.tp_ListId = @p0 and (DepartmentTable.Title = @p1)       

public class BaseEntity
{
    public virtual int Id { get; set; }
    public virtual string Name { get; set; } 
}
public class Employee : BaseEntity
{
    public virtual Department Department { get; set; } // to lookup record
}
public class Department : BaseEntity
{
    public virtual IList<Employee> Employees { get; set; } // the way back 
}

<class name="Department" table="[dbo].[AllData]" lazy="true" batch-size="25" 
    where="LookupColumn1Id IS NULL" >
  <id name="Id" column="Id" generator="native" />

  <property not-null="true"  name="Name" column="Title" />

  <bag name="Employees" >
    <key column="LookupColumn1Id" />
    <one-to-many class="Employee"/>
  </bag>

</class>

<class name="Employee1" table="[dbo].[AllData]" lazy="true" batch-size="25"
  where="LookupColumn1Id IS NOT NULL" >
  <id name="Id" column="Id" generator="native" />

  <property not-null="true"  name="Name" column="Title" />

  <many-to-one name="Department" class="Department" column="LookupColumn1Id " />
</class>

映射可以如下所示：

SELECT EmployeeTable.Title, DepartmentTable.Id, DepartmentTable.Title
FROM AllData EmployeeTable left outer join AllData DepartmentTable on EmployeeTable.LookupColumn1Id=DepartmentTable.Id       
WHERE EmployeeTable.tp_ListId = @p0 and (DepartmentTable.Title = @p1)       

public class BaseEntity
{
    public virtual int Id { get; set; }
    public virtual string Name { get; set; } 
}
public class Employee : BaseEntity
{
    public virtual Department Department { get; set; } // to lookup record
}
public class Department : BaseEntity
{
    public virtual IList<Employee> Employees { get; set; } // the way back 
}

<class name="Department" table="[dbo].[AllData]" lazy="true" batch-size="25" 
    where="LookupColumn1Id IS NULL" >
  <id name="Id" column="Id" generator="native" />

  <property not-null="true"  name="Name" column="Title" />

  <bag name="Employees" >
    <key column="LookupColumn1Id" />
    <one-to-many class="Employee"/>
  </bag>

</class>

<class name="Employee1" table="[dbo].[AllData]" lazy="true" batch-size="25"
  where="LookupColumn1Id IS NOT NULL" >
  <id name="Id" column="Id" generator="native" />

  <property not-null="true"  name="Name" column="Title" />

  <many-to-one name="Department" class="Department" column="LookupColumn1Id " />
</class>

此映射，对于读取访问，所需的SELECT正在工作。现在，我们可以创建一个查询：

[TestMethod]
public void TestAllData()
{
    var session = NHSession.GetCurrent();

    // the Employee Criteria
    var criteria = session.CreateCriteria<Employee>();
    // joined with the Department
    var deptCrit = criteria.CreateCriteria("Department", JoinType.LeftOuterJoin);

    // here we can filter Department
    deptCrit.Add(Restrictions.Eq("Name", "Dep Name"));
    // here we can filter Employee
    criteria.Add(Restrictions.Eq("Name", "Emp Name"));


    // the SELECT
    var results = criteria
        .List<Employee>();

    Assert.IsTrue(results.IsNotEmpty());

    var employee = results.First();

    // check if all data are injected into our properties
    Assert.IsTrue(employee.Name.IsNotEmpty());
    Assert.IsTrue(employee.Department.Name.IsNotEmpty());
}

这个场景通常可以工作，但我们所做的是，只在C中进行继承，这两者都是从BaseEntity派生的，而不是在映射中

---

原因是，缺少将起到鉴别器作用的列。这就是为什么我们在xml中使用带有WHERE属性see class元素的映射，通过查找列presence区分部门和员工

谢谢，但这不是答案。我不会在代码中显式地实现该层上实体之间的关系，我只想在映射中指定特定的关系。换句话说，您正在将表访问移到实体/对象访问。这意味着，我们必须将表映射到实体，根据它们的数据库和对象结构创建关系。然后我们可以通过对象模型的抽象来查询数据库