ORM之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

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

2)获取连接数据库对象

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

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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  

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

封装

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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

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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

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//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<Users> list = new List<Users>();         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<Users>(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<Users> user = conn.Query<Users>(sqlCommandText).ToList();     }

3.防止Sql注入

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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<User>(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<MSys_Admin>(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

[TestMethod]
 public void TestDapperTransaction()
 {
     using (var conn = new MySql.Data.MySqlClient.MySqlConnection("server=localhost;User Id=root;password=root;Database=test"))
     {
         conn.Open();
         IDbTransaction trans = conn.BeginTransaction();
         int row = conn.Execute(@"update t set name='www.lanhusoft.com' where id=@id", new { id = 3 }, trans);
         row += conn.Execute("delete from t where id=@id", new { id = 5 }, trans);
         for (int i = 0; i < 100; i++)
         {
             conn.Execute(@"insert t(id, name) values (@id, @name)", new { id = i, name = "www.lanhusoft.com/" + i });
         }
         trans.Commit();
         conn.Close();
     }
 }