NHibernate - 基本 CRUD 操作
在本章中,我们将介绍基本 CRUD 操作。现在我们的系统已准备好启动,因为我们已经成功实现了域 Student 类,我们还定义了映射文件并配置了 NHibernate。我们现在可以使用一些查询来执行 CRUD 操作。
创建数据
如您所见,NHibernateDemoDB 数据库中的 Student 表中没有数据。

因此,要添加一些数据,我们需要执行如下所示的 添加/创建 操作。
using (var session = sefact.OpenSession()) {
using (var tx = session.BeginTransaction()) {
var student1 = new Student {
ID = 1,
FirstMidName = "Allan",
LastName = "Bommer"
};
var student2 = new Student {
ID = 2,
FirstMidName = "Jerry",
LastName = "Lewis"
};
session.Save(student1);
session.Save(student2);
tx.Commit();
}
Console.ReadLine();
}
如您所见,我们创建了两个学生,然后调用 OpenSession 的 Save() 方法,然后调用 BeginTransaction 的 Commit()。以下是 Program.cs 文件中的完整实现
using NHibernate.Cfg;
using NHibernate.Dialect;
using NHibernate.Driver;
using System;
using System.Linq;
using System.Reflection;
namespace NHibernateDemoApp {
class Program {
static void Main(string[] args) {
var cfg = new Configuration();
String Data Source = asia13797\sqlexpress;
String Initial Catalog = NHibernateDemoDB;
String Integrated Security = True;
String Connect Timeout = 15;
String Encrypt = False;
String TrustServerCertificate = False;
String ApplicationIntent = ReadWrite;
String MultiSubnetFailover = False;
cfg.DataBaseIntegration(x = > { x.ConnectionString = "Data Source +
Initial Catalog + Integrated Security + Connect Timeout + Encrypt +
TrustServerCertificate + ApplicationIntent + MultiSubnetFailover";
x.Driver<SqlClientDriver>();
x.Dialect<MsSql2008Dialect>();
});
cfg.AddAssembly(Assembly.GetExecutingAssembly());
var sefact = cfg.BuildSessionFactory();
using (var session = sefact.OpenSession()) {
using (var tx = session.BeginTransaction()) {
var student1 = new Student {
ID = 1,
FirstMidName = "Allan",
LastName = "Bommer"
};
var student2 = new Student {
ID = 2,
FirstMidName = "Jerry",
LastName = "Lewis"
};
session.Save(student1);
session.Save(student2);
tx.Commit();
}
Console.ReadLine();
}
}
}
}
现在让我们运行此应用程序,然后转到 SQL Server Object Explorer 并刷新数据库。您将看到上述两名学生现在已添加到 NHibernateDemoDB 数据库中的 Student 表中。

从 Student 表中读取数据
您可以看到现在我们的 student 表中有两条记录。要从表中读取这些记录,我们需要调用 OpenSession 的 CreateCriteria(),如以下代码所示。
using (var session = sefact.OpenSession()) {
using (var tx = session.BeginTransaction()) {
var students = session.CreateCriteria<Student>().List<Student>();
foreach (var student in students) {
Console.WriteLine("{0} {1} {2}",
student.ID,student.FirstMidName, student.LastName);
}
tx.Commit();
}
Console.ReadLine();
}
因此,如果您想要记录列表,那么我们只需简单地说学生类型的列表即可。
现在使用 foreach 遍历所有学生,并在控制台上打印 ID、FirstMidName 和 LastName。现在,让我们再次运行此应用程序,您将在控制台窗口中看到以下输出。
1 Allan Bommer 2 Jerry Lewis
您还可以使用以下代码在 OpenSession 的 Get() 方法中指定 ID 来检索任何记录。
using (var session = sefact.OpenSession()) {
using (var tx = session.BeginTransaction()) {
var students = session.CreateCriteria<Student>().List<Student>();
foreach (var student in students) {
Console.WriteLine("{0} {1} {2}", student.ID,
student.FirstMidName, student.LastName);
}
var stdnt = session.Get<Student>(1);
Console.WriteLine("Retrieved by ID");
Console.WriteLine("{0} {1} {2}", stdnt.ID,
stdnt.FirstMidName, stdnt.LastName);
tx.Commit();
}
Console.ReadLine();
}
现在,当您运行应用程序时,您将看到以下输出。
1 Allan Bommer 2 Jerry Lewis Retrieved by ID 1 Allan Bommer
更新记录
要更新表中的记录,我们需要先获取该特定记录,然后通过调用 OpenSession 的 Update() 方法来更新该记录,如以下代码所示。
using (var session = sefact.OpenSession()) {
using (var tx = session.BeginTransaction()) {
var students = session.CreateCriteria<Student>().List<Student>();
foreach (var student in students) {
Console.WriteLine("{0} {1} {2}", student.ID,
student.FirstMidName, student.LastName);
}
var stdnt = session.Get<Student>(1);
Console.WriteLine("Retrieved by ID");
Console.WriteLine("{0} {1} {2}", stdnt.ID, stdnt.FirstMidName, stdnt.LastName);
Console.WriteLine("Update the last name of ID = {0}", stdnt.ID);
stdnt.LastName = "Donald";
session.Update(stdnt);
Console.WriteLine("
Fetch the complete list again
");
foreach (var student in students) {
Console.WriteLine("{0} {1} {2}", student.ID,
student.FirstMidName, student.LastName);
}
tx.Commit();
}
Console.ReadLine();
}
现在,当您运行应用程序时,您将看到以下输出。
1 Allan Bommer 2 Jerry Lewis Retrieved by ID 1 Allan Bommer Update the last name of ID = 1 Fetch the complete list again 1 Allan Donald 2 Jerry Lewis
如您所见,ID 等于 1 的 LastName 从 Bommer 更新为 Donald。
删除记录
要从表中删除任何记录,我们需要先获取该特定记录,然后通过调用 OpenSession 的 Delete() 方法删除该记录,如以下代码所示。
using (var session = sefact.OpenSession()) {
using (var tx = session.BeginTransaction()) {
var students = session.CreateCriteria<Student>().List<Student>();
foreach (var student in students) {
Console.WriteLine("{0} {1} {2}", student.ID,
student.FirstMidName, student.LastName);
}
var stdnt = session.Get<Student>(1);
Console.WriteLine("Retrieved by ID");
Console.WriteLine("{0} {1} {2}", stdnt.ID, stdnt.FirstMidName, stdnt.LastName);
Console.WriteLine("Delete the record which has ID = {0}", stdnt.ID);
session.Delete(stdnt);
Console.WriteLine("
Fetch the complete list again
");
foreach (var student in students) {
Console.WriteLine("{0} {1} {2}", student.ID, student.FirstMidName,
student.LastName);
}
tx.Commit();
}
Console.ReadLine();
}
现在,当您运行应用程序时,您将看到以下输出。
1 Allan Donald 2 Jerry Lewis Retrieved by ID 1 Allan Bommer Delete the record which has ID = 1 Fetch the complete list again 2 Jerry Lewis
如您所见,数据库中 ID 等于 1 的记录不再可用。您还可以在 SQL Server 对象资源管理器中查看数据库。
