轻量级ORM框架Dapper应用二：使用Dapper实现CURD操作

在上一篇文章中，讲解了如何安装Dapper，这篇文章中将会讲解如何使用Dapper使用CURD操作。

例子中使用到的实体类定义如下：

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 
 7 namespace DapperApplicationDemo.Model
 8 {
 9    public class User
10     {
11         public int UserId { get; set; }
12 
13         public string UserName { get; set; }
14 
15         public string Email { get; set; }
16 
17         public string Address { get; set; }
18     }
19 }

注意：在使用下面的方法之前要首先引入Dapper的命名空间：Using Dapper;

一、插入数据

1、使用匿名类插入数据

IDbConnection connection = new SqlConnection(conn);
var result = connection.Execute(
"Insert into Users values (@UserName, @Email, @Address)",
new { UserName = "Tom", Email = "747954712@qq.com", Address = "北京" });

查询数据库：

2、使用实体类插入数据

string sqlCommandText = "insert into Users(UserName,Email,Address) Values (@UserName,@Email,@Address)";
using (IDbConnection connection = new SqlConnection(conn))
{
      User user = new User()
      {
           UserName = "tim",
           Email = "78415155@qq.com",
           Address = "北京"
       };
      int result = connection.Execute(sqlCommandText,user);
      if (result > 0)
      {
          Console.WriteLine("插入成功!");
      }
      else
      {
          Console.WriteLine("插入失败!");
      }
}

查询数据库：

3、InsertBulk操作

既然是Bulk操作，那肯定就是批量插入了，我们要做的就是将上面使用到的“匿名对象”变成“匿名对象集合”就可以了，代码如下：

using (IDbConnection connection = new SqlConnection(conn))
{
         var userList = Enumerable.Range(1012, 100000).Select(i => new User()
         {
                Email = i + "qq.com",
                Address = "北京",
                UserName = "CK" + i,
          });
          var result = connection.Execute("insert into Users values(@UserName,@Email,@Address)", userList);
}

查询数据库：

二、查询数据

using (IDbConnection connection = new SqlConnection(conn))
{
        // 查询
        var query = connection.Query<User>("SELECT * FROM Users");
        query.AsList().ForEach(p => 
        {
              Console.WriteLine("Id:"+p.UserId+" UserName:"+p.UserName+" Email:"+p.Email+" Address:"+p.Address);
        });
}

程序运行结果：

三、更新数据

1、使用匿名类更新

using (IDbConnection connection = new SqlConnection(conn))
{
       var result = connection.Execute("update Users set UserName='Tim',Address='上海' where UserId=@UserId", new { UserId = 2 });
}

查询数据库：

2、使用实体类更新

using (IDbConnection connection = new SqlConnection(conn))
{
        User user = new User();
        user.UserName = "张无忌";
        user.UserId = 1;
        var result = connection.Execute("update Users set UserName=@UserName where UserId=@UserId", user);
}

查询数据库：

3、使用键值对更新

using (IDbConnection connection = new SqlConnection(conn))
{
       List<KeyValuePair<string, object>> keys = new List<KeyValuePair<string, object>>();
       keys.Add(new KeyValuePair<string, object>("@UserName", "风清扬"));
       keys.Add(new KeyValuePair<string, object>("@UserId", 2));
       var result = connection.Execute("update Users set UserName=@UserName where UserId=@UserId", keys);
}

查询数据库：

四、删除数据

1、使用匿名类删除数据

using (IDbConnection connection = new SqlConnection(conn))
{
       var result = connection.Execute("delete from Users where UserId=@UserId", new { UserId = 3 });
}

2、使用实体类删除数据

using (IDbConnection connection = new SqlConnection(conn))
{
        User user = new User();
        user.UserId = 4;
        var result = connection.Execute("delete from Users where UserId=@UserId", user);
}

示例程序代码下载地址：https://pan.baidu.com/s/1nvaJ8LV