Dapper操作Sql Server和MySql数据库

1.为什么选择Dapper

1)轻量。

2)速度快。Dapper的速度接近与IDataReader，取列表的数据超过了DataTable。

3)支持多种数据库。Dapper可以在所有Ado.net Providers下工作，包括sqlite, sqlce, firebird, oracle, MySQL, PostgreSQL and SQL Server

4)可以映射一对一，一对多，多对多等多种关系。

5)性能高。通过Emit反射IDataReader的序列队列，来快速的得到和产生对象，性能不错。

6)支持FrameWork2.0，3.0，3.5，4.0，4.5

7)Dapper语法十分简单。并且无须迁就数据库的设计

2.使用教程

1)在配置文件web.config中添加连接字符串

  "sqlconnectionString"  connectionString= "server=127.0.0.1;database=MyDataBase;User=sa;password=123456;Connect Timeout=1000000" />
  "mysqlconnectionString"  connectionString= "Database=hyd;Data Source=127.0.0.1;User Id=root;Password=root;CharSet=utf8;port=3306" />

2)获取连接数据库对象

  获取Sql Server的连接数据库对象:SqlConnection  

public  static  SqlConnection SqlConnection()
        {
            string  sqlconnectionString = ConfigurationManager.ConnectionStrings[ "sqlconnectionString" ].ToString();
            var  connection =  new  SqlConnection(sqlconnectionString);
            connection.Open();
            return  connection;
        }

　获取MySql的连接数据库对象:MySqlConnection  

public  static  MySqlConnection MySqlConnection()
   {
       string  mysqlconnectionString = ConfigurationManager.ConnectionStrings[ "mysqlconnectionString" ].ToString();
       var  connection =  new  MySqlConnection(mysqlconnectionString);
       connection.Open();
       return  connection;
   }

封装

public  class  DapperService
    {
        public  static  SqlConnection SqlConnection()
        {
            string  sqlconnectionString = ConfigurationManager.ConnectionStrings[ "sqlconnectionString" ].ToString();
            var  connection =  new  SqlConnection(sqlconnectionString);
            connection.Open();
            return  connection;
        }
        public  static  MySqlConnection MySqlConnection()
        {
            string  mysqlconnectionString = ConfigurationManager.ConnectionStrings[ "mysqlconnectionString" ].ToString();
            var  connection =  new  MySqlConnection(mysqlconnectionString);
            connection.Open();
            return  connection;
        }
    }

3)实体类

public  class  Users
 {
     public  int  ID {  get ;  set ; } //自增主键
     public  string  Name {  get ;  set ; }
     public  int   Age {  get ;  set ; }
 }

4)增删改查

//增
    using  (IDbConnection conn = DapperService.MySqlConnection())
    {
        Users user =  new  Users();
        user.Name =  "CNKI" ;
        user.Age = 38;
        string  sqlCommandText =  @"INSERT INTO USERS(Name,Age)VALUES(@Name,@Age)" ;
        int  result = conn.Execute(sqlCommandText, user);
    }
  //批量增
    using  (IDbConnection conn = DapperService.MySqlConnection())
    {
        List list =  new  List();
        for  ( int  i = 0; i < 5; i++)
        {
            Users user =  new  Users();
            user.Name =  "CNKI" ;
            user.Age = 38;
            list.Add(user);
        }
        string  sqlCommandText =  @"INSERT INTO USERS(Name,Age)VALUES(@Name,@Age)" ;
        int  result = conn.Execute(sqlCommandText, list);
    }
    //删
    using  (IDbConnection conn = DapperService.MySqlConnection())
    {
        Users user =  new  Users();
        user.ID = 1;
        string  sqlCommandText =  @"DELETE FROM USERS WHERE ID=@ID" ;
        int  result = conn.Execute(sqlCommandText, user);
    }
    //改
    using  (IDbConnection conn = DapperService.MySqlConnection())
    {
        Users user =  new  Users();
        user.ID = 2;
        user.Name =  "CNKI" ;
        user.Age = 18;
        string  sqlCommandText =  @"UPDATE USERS SET Age=@Age WHERE ID=@ID" ;
        int  result = conn.Execute(sqlCommandText, user);
    }
    //查
    using  (IDbConnection conn = DapperService.MySqlConnection())
    {
        string  sqlCommandText =  @"SELECT * FROM USERS WHERE ID=@ID" ;
        Users user = conn.Query(sqlCommandText,  new   { ID=2 }).FirstOrDefault();
    }
   //分页
    using  (IDbConnection conn = DapperService.MySqlConnection())
    {
        int  pageIndex = 0;
        int  pageSize = 2;
        string  sqlCommandText =  string .Format( @"SELECT * FROM USERS  LIMIT {0},{1} " , pageIndex * pageSize, pageSize);
        List user = conn.Query(sqlCommandText).ToList();
    }

3.防止Sql注入

using  (IDbConnection conn = DapperService.MySqlConnection())
 {
     string  sqlCommandText =  @"SELECT * FROM USER WHERE ID=@ID" ;
     var  p =  new  DynamicParameters();
     p.Add( "@ID" , 1);
     User user2 = conn.Query(sqlCommandText,p).FirstOrDefault();
 }

这要用到了Dapper的DynamicParameters动态参数集合类，从上面可以看到可以能过Add方法加入参数。最后通过conn.Query(sqlText, p)执行sql,，返回结果。因为用的是命令参数的形式，让sql注入无机可乘，所以这种方案是安全的。

4.操作事物

 1 [TestMethod]
 2  public void TestDapperTransaction()
 3  {
 4      using (var conn = new MySql.Data.MySqlClient.MySqlConnection("server=localhost;User Id=root;password=root;Database=test"))
 5      {
 6          conn.Open();
 7          IDbTransaction trans = conn.BeginTransaction();
 8          int row = conn.Execute(@"update t set name='www.lanhusoft.com' where id=@id", new { id = 3 }, trans);
 9          row += conn.Execute("delete from t where id=@id", new { id = 5 }, trans);
10          for (int i = 0; i < 100; i++)
11          {
12              conn.Execute(@"insert t(id, name) values (@id, @name)", new { id = i, name = "www.lanhusoft.com/" + i });
13          }
14          trans.Commit();
15          conn.Close();
16      }
17  }
参见:
http://www.cnblogs.com/cnki/p/5723426.html