我们知道, 对于数据库中的一对多关系, 我们在建表的时候, 应该在多表这里建立外键
我们准备这样一个场景, 大学里的系和学生, 一个系有多个学生
Department类和Xml如下:
Department.cs
using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace NHibernate3.Domain { public class Department { public virtual int? ID { get; set; } public virtual string Name { get; set; } } }
Department..hbm.xml
<? xml version="1.0" encoding="utf-8" ?> < hibernate-mapping xmlns ="urn:nhibernate-mapping-2.2" assembly ="NHibernate3.Domain" namespace ="NHibernate3.Domain" > < class name ="Department" table ="T_Department" lazy ="true" > < id name ="ID" type ="int" column ="DepartmentID" > < generator class ="native" /> </ id > < property name ="Name" type ="string" > < column name ="Name" length ="50" /> </ property > </ class > </ hibernate-mapping >
Student类和Xml如下:
Student.cs
using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace NHibernate3.Domain { public class Student { public virtual int? ID { get; set; } public virtual string Name { get; set; } public virtual Department Dept { get; set; } } }
Student.hbm.xml
<? xml version="1.0" encoding="utf-8" ?> < hibernate-mapping xmlns ="urn:nhibernate-mapping-2.2" assembly ="NHibernate3.Domain" namespace ="NHibernate3.Domain" > < class name ="Student" table ="T_Student" lazy ="true" > < id name ="ID" type ="int" column ="StudentID" > < generator class ="native" /> </ id > < property name ="Name" type ="string" > < column name ="Name" length ="50" /> </ property > < many-to-one name ="Dept" column ="DepartmentID" cascade ="all" /> </ class > </ hibernate-mapping >
保存和查询代码
ScSession.cs
using System; using System.Collections.Generic; using System.Linq; using System.Text; using NHibernate; using NHibernate.Cfg; using NHibernate3.Domain; namespace NHibernate3.DAL { public class ScSession { private ISessionFactory sessionFactory; public ScSession() { var cfg = new NHibernate.Cfg.Configuration().Configure( " Config/hibernate.cfg.xml "); sessionFactory = cfg.BuildSessionFactory(); } public void Save() { using (ISession session = this.sessionFactory.OpenSession()) { var dept = new Department { Name = " 计算机系 " }; var student1 = new Student { Name = " 李四 ", Dept = dept }; var student2 = new Student { Name = " 张三 ", Dept = dept }; ITransaction tran = session.BeginTransaction(); try { // 持久化Department类 session.Save(student1); session.Save(student2); tran.Commit(); } catch (Exception ex) { tran.Rollback(); throw ex; } } } public void GetAll() { using (ISession session = this.sessionFactory.OpenSession()) { var students = session.CreateQuery( " from Student ").List<Student>(); Console.WriteLine(); Console.WriteLine( " ******* 学生信息 ******* "); foreach (Student student in students) { Console.WriteLine( " 学生：{0} ", student.Name); Console.WriteLine( " 系：{0} ", student.Dept.Name); } } } } }
运行结果:
记录保存成功!
******* 学生信息 *******
学生：李四系：计算机系学生：张三系：计算机系