NHibernate的多对多的关系映射 [英] Nhibernate many to many relationship mapping

问题描述

我很新NHibernate的。我想使用NHibernate作为映射数据库工具来开发asp.net应用程序。

I am very new to Nhibernate. I would like to develop an application in asp.net by using NHibernate as mapping database tools.

我有以下表模式：

CREATE TABLE [dbo].[tblTeam](
    [TeamID] [int] IDENTITY(1,1) NOT NULL,
    [TeamName] [varchar](100) NOT NULL
)


CREATE TABLE [dbo].[tblEmployee](
    [EmployeeID] [int] IDENTITY(1,1) NOT NULL,
    [EmployeeName] [varchar](100) NOT NULL
)

CREATE TABLE [dbo].[tblTeamEmployee](
    [TeamID] [int] NOT NULL,
    [EmployeeID] [int] NOT NULL
)

这是我做了NHibernate的映射文件：

And here is Nhibernate mapping file that I have made:

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
  <class name="TelDir.Core.Domain.Team, TelDir.Core" table="tblTeam" lazy="false">
    <id name="ID" column="TeamID" unsaved-value="0">
      <generator class="identity" />
    </id>

    <property name="TeamName" column="TeamName" />

    <bag name="Employees" cascade="none" table="tblTeamEmployee" lazy="false" access="readonly">
      <key column="EmployeeID"/>
      <many-to-many class="TelDir.Core.Domain.Employee, TelDir.Core" column="TeamID"/>
    </bag>

  </class>
</hibernate-mapping>


<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
  <class name="TelDir.Core.Domain.Employee, TelDir.Core" table="tblEmployee" lazy="false">
    <id name="ID" column="EmployeeID" unsaved-value="0">
      <generator class="identity" />
    </id>

    <property name="EmployeeName" column="EmployeeName" />        

    <bag name="Teams" cascade="none" table="tblTeamEmployee" lazy="false" >
      <key column="EmployeeID"/>
      <many-to-many class="TelDir.Core.Domain.Team, TelDir.Core" column="EmployeeID"/>
    </bag>

  </class>
</hibernate-mapping>

和我的POCO类定义如下：

And my POCO class is defined as below:

namespace TelDir.Core.Domain
{
    public class Team   {

        private string _TeamName = "";
        private IList<Employee> _employees = new List<Employee>();

        public Team() { }

        public  string TeamName {
            get { return _TeamName }
            set { _TeamName = value; }
        }


        public  IList<Employee> Employees
        {
            get { return new List<Employee>(_employees).AsReadOnly(); }
            protected set { _employees = value; }          
        }

        public  void AddEmployee(Employee em)
        {
            if (!_employees.Contains(em)){
                _employees.Add(em);
            }
        }

        public  void RemoveEmployee(Employee em)
        {
            if (_employees.Contains(em)){
                _employees.Remove(em);
            }
        }  
    }
}




namespace TelDir.Core.Domain
{
    public class Employee  {

        private string _EmployeeName = "";
        private IList<Team> _teams = new List<Team>();

        public Employee() { }

        public  string EmployeeName {
            get { return _EmployeeName}
            set { _EmployeeName = value; }
        }


        public  IList<Team> Teams
        {
            get { return new List<Team>(_teams).AsReadOnly(); }
            protected set { _teams = value; }          
        }

        public  void AddTeam(Team tm)
        {
            if (!_teams.Contains(tm)){
                _teams.Add(tm);
            }
        }

        public  void RemoveTeam(Team tm)
        {
            if (_teams.Contains(tm)){
                _teams.Remove(tm);
            }
        }  
    }
}

我不知道我的映射和实体类是否明确？

I am not sure whether my mapping and entity class is well defined?

假如我有以下我的表中的数据

Suppose I have following data in my table

tblTeam
        TeamID     |      TeamName
        --------------------------
          1        |         A
        --------------------------
          2        |         B

tblEmployee
        EmployeeID |      EmployeeName
        ------------------------------
          1        |      Jhon
        ------------------------------
          2        |      Michel
        ------------------------------
          3        |      Lino

tblTeamEmployee
        TeamID     |      EmployeeID
        ------------------------------
          1        |      1
        ------------------------------
          1        |      2
        ------------------------------
          2        |      3
        ------------------------------
          2        |      1        

我如何删除员工姓名='约翰'在ASP.NET页面团队='B'？

How can I remove Employee name='Jhon' from Team='B' in ASP.NET page?

推荐答案

当你想改变你的收藏，删除 .AsReadOnly（）从它。

As you want to change your collection, remove the .AsReadOnly() from it.

然后，如果你同时拥有的ID（1和2），只是做：

Then, if you have the ids of both (1 and 2), just do:

var teamB = session.Get<Team>(2);
teamB.Employees.Remove(teamB);
session.Flush();

这篇关于NHibernate的多对多的关系映射的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！