MySqlCommand创建-优快云博客

本文链接：https://blog.youkuaiyun.com/againknow/article/details/128437487

本文介绍了如何在C#中创建并使用MysqlCommand对象来执行SQL命令。从不带参数的基本创建到带参数的高级用法，包括单参数和双参数的配置方法。

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前期准备

安装MySql.Data 包
在这里插入图片描述
配置外部文件

<connectionStrings>
		<add name="connStr"
		     connectionString="server=localhost;database=mysql_student;uid=root;pwd=123456"
			 providerName="MySql.Data.MySqlClient"/>
	</connectionStrings>

一、MysqlCommand 不带参数

MySqlCommand cmd = connect.CreateCommand();
cmd.CommandText = sql;
cmd.Connection = connect;

internal class Program
    {
        static void Main(string[] args)
        {
            //获取外部文件字符串
            string connStr = ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;
            using (MySqlConnection connect = new MySqlConnection(connStr))
            {
                connect.Open();
                string sql = "show databases;";
                //MysqlCommand 命令创建  不带参数
                MySqlCommand cmd = connect.CreateCommand();
                cmd.CommandText = sql;
                cmd.Connection = connect;

                MySqlDataReader reader = cmd.ExecuteReader();
                while (reader.Read())
                {
                    Console.WriteLine(reader[0]);
                }
                reader.Close();
                //connect.Close(); //自动关闭
            }
            Console.WriteLine("Hello World!");
        }
    }

二、MysqlCommand 带一个参数

MySqlCommand cmd = new MySqlCommand(sql);
cmd.Connection = connect;

  internal class Program
    {
        static void Main(string[] args)
        {
            //获取外部文件字符串
            string connStr = ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;
            using (MySqlConnection connect = new MySqlConnection(connStr))
            {
                connect.Open();
                string sql = "show databases;";
                //MysqlCommand 命令创建  带一个参数
                MySqlCommand cmd = new MySqlCommand(sql);
                cmd.Connection = connect;

                MySqlDataReader reader = cmd.ExecuteReader();
                while (reader.Read())
                {
                    Console.WriteLine(reader[0]);
                }
                reader.Close();
                //connect.Close(); //自动关闭
            }
            Console.WriteLine("Hello World!");
        }
    }

三、MysqlCommand 带两个参数 (推荐)

MySqlCommand cmd = new MySqlCommand(sql, connect);

   internal class Program
    {
        static void Main(string[] args)
        {
            //获取外部文件字符串
            string connStr = ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;
            using (MySqlConnection connect = new MySqlConnection(connStr))
            {
                connect.Open();
                string sql = "show databases;";
                //MysqlCommand 命令创建  带两个参数 (推荐)
                MySqlCommand cmd = new MySqlCommand(sql, connect);

                MySqlDataReader reader = cmd.ExecuteReader();
                while (reader.Read())
                {
                    Console.WriteLine(reader[0]);
                }
                reader.Close();
                //connect.Close(); //自动关闭
            }
            Console.WriteLine("Hello World!");
        }
    }