c#mysql修改_C#--MySQL数据库基本操作（增、删、改、
查）
写在前⾯：
常⽤数据库：
在⽇常的⼯作中，通常⼀个项⽬会⼤量⽤的数据库的各种基本操作，因此⼩编⼏个常见的数据库的操作封装成了⼀个dll⽅便后续的开发使⽤。本⽂则主要是记录了C#对MySQL的连接、增、删、改、查的基本操作，如有什么问题还请各位⼤佬指教。后续也将对其他⼏个常⽤的数据库进⾏相应的整理。话不多说，直接开始码代码。
引⽤：
MySQL的引⽤需要去⼿动下载
using MySql.Data.MySqlClient;  //MySQL引⽤集
using System.Data; //DataSet引⽤集
先声明⼀个MySqlConnection 便于后续使⽤。
private MySqlConnection mysql_con;
MySQL打开：
///
/// MySQL open
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///
/// link statement
/// Success:success; Fail:reason
public string MySQL_Open(string link)
{
try
{
mysql_con = new MySqlConnection(link);
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return "success";
}
catch (Exception ex)
{
return ex.Message;
}
}实例u2vip
MySQL关闭：
/
// MySQL close
///
/// Success:success Fail:reason
public string MySQL_Close()
{
try
{
if (mysql_con == null)
{
return "No database connection";
}
if (mysql_con.State == ConnectionState.Open || mysql_con.State == ConnectionState.Connecting) {
mysql_con.Close();
mysql_con.Dispose();
}
else
{
if (mysql_con.State == ConnectionState.Closed)
{
return "success";
}
if (mysql_con.State == ConnectionState.Broken)
{
return "ConnectionState:Broken";
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}
}
return "success";
}
catch (Exception ex)
{
return ex.Message;
}
MySQL的增删改：
/
//
/// MySQL insert,delete,update
///
/// insert,delete,update statement
/// Success:success + Number of affected rows; Fail:reason
public string MySQL_Insdelupd(string sql)
{
try
{
int num = 0;
if (mysql_con == null)
{
return "Please open the database connection first";
}
if (mysql_con.State == ConnectionState.Open)
{
MySqlCommand sqlCommand = new MySqlCommand(sql, mysql_con); num = sqlCommand.ExecuteNonQuery();
}
else
{
if (mysql_con.State == ConnectionState.Closed)
{
return "Database connection closed";
}
if (mysql_con.State == ConnectionState.Broken)
{
return "Database connection is destroyed";
}
if (mysql_con.State == ConnectionState.Connecting)
{
return "The database is in connection";
}
return "success" + num;
}
catch (Exception ex)
{
return ex.Message.ToString();
}
}
MySQL的查：
///
/// MySQL select
///
/// select statement
/
// Success:success; Fail:reason
/// select result
public DataSet MySQL_Select(string sql, out string record)
{
try
{
//储存数据的⼯具初始化
androidstudio简单程序DataSet dataSet = new DataSet();
if (mysql_con == null)
{
record = "Please open the database connection first";
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return dataSet;
}
if (mysql_con.State == ConnectionState.Open)
{
MySqlDataAdapter sqlDataAdapter = new MySqlDataAdapter(sql, mysql_con); sqlDataAdapter.Fill(dataSet, "sample");
sqlDataAdapter.Dispose();
record = "success";
return dataSet;
if (mysql_con.State == ConnectionState.Closed)
{
record = "Database connection closed";
return dataSet;
}
if (mysql_con.State == ConnectionState.Broken)
{
record = "Database connection is destroyed";
return dataSet;
}
if (mysql_con.State == ConnectionState.Connecting)
{
record = "The database is in connection";
return dataSet;
}
record = "ERROR";
return dataSet;
}
catch (Exception ex)
{
DataSet dataSet = new DataSet();
record = ex.Message.ToString();
return dataSet;
}
}
⼩编发现以上这种封装⽅式还是很⿇烦，每次对MySQL进⾏增删改查的时候还得先打开数据库，最后还要关闭，实际运⽤起来⽐较⿇烦。因此对上⾯两个增删改查的⽅法进⾏了重载，在每次进⾏操作时都先打开数据库，然后关闭数据库。
///
/// MySQL insert,delete,update
///
/// insert,delete,update statement
/// link statement
/// Success:success + Number of affected rows; Fail:reason

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