使用NHibernate从多个条件表中选择列

Question

我有一个实体类，它有3列; entityType，entityID和EntityText。例如：如果实体类型为3（contact），entityID为2，它将加入到Contacts表中，并通过entityID获取联系人，并将contact.name属性设置为EntityText。我怎样才能做到这一点？

详情： 不同的对象类。

Contact 
{ 
contactID 
firstName 
lastName 
.. 
} 
Company 
{ 
companyID 
name 
address 
... 
} 
Task{ 
taskID 
entityID 
entityType 
entityText= Company.name or Contact.firstName + Contact.lastName 
... 
} 

Answer 1

编辑：重构相匹配的更新问题

因为EntityText的内容背后的逻辑，我会prefere多态性

public abstract class Task 
{ 
    public virtual int Id { get; set; } 
    public abstract string Text { get; set; } 
} 

public class ContactTask : Task 
{ 
    public virtual Contact Contact { get; set; } 
    public override string Text 
    { 
     get { return Contact.FirstName + " " + Contact.LastName; } 
     set { Contact.FirstName = value.Split(' ')[0]; Contact.LastName = value.Split(' ')[1]; } 
    } 
} 
public class CompanyTask : Task 
{ 
    public virtual Company Company { get; set; } 
    public override string Text 
    { 
     get { return Company.Name; } 
     set { Company.Name = value; } 
    } 
} 

public class TaskMap : ClassMap<Task> 
{ 
    public TaskMap() 
    { 
     Table("TaskTable"); 

     Id(c => c.Id, "taskID").GeneratedBy....(); 
     DiscriminateSubclassesOn("entityType"); 
    } 
} 

public class ContactTaskMap : ClassMap<ContactTask> 
{ 
    public ContactTaskMap() 
    { 
     DiscriminatorValue(3); 
     References(ct => ct.Contact, "entityID"); 
    } 
} 

public class CompanyTaskMap : ClassMap<CompanyTask> 
{ 
    public ContactTaskMap() 
    { 
     DiscriminatorValue(2); 
     References(ct => ct.Company, "entityID"); 
    } 
} 

// get all tasks 
var all = session.QueryOver<Task>().List(); 

// get all tasks for Company 
var companyTasks = session.QueryOver<CompanyTask>().List();