地图企业自我连接表凭身份证

Question

我的遗留表“ALLDATA”有这些列：Id, Title, 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; } 
} 

我要生成选择这样的：

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)  

Answer 1

设我告诉你，其中一个选项。对于这个草稿，我期望，那些具有LookupColumn1Id NULL的记录将扮演Department的角色，其余将扮演Employee的角色。

实体看起来是这样的：

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 
} 

的映射可能是这样的：

<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> 

这种映射，读访问（要求SELECT）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()); 
} 

这种情况在一般的工作，但我们所做的，只是在C＃中（无论是从BaseEntity派生）继承，而不是在映射。

原因是，缺失的列将扮演Discriminator角色。这就是为什么我们使用WHERE属性的映射（请参阅xml中的类元素），通过查找列存在区分Department和Employee