C# MariaDB 连接，关闭，创建、增、删、查、改

最近项目用到C# 以及MariaDB相关知识，在此小计一下。

关于MariaDB的安装使用参照以下连接文档：

MariaDB安装与使用_HeidiSQL工具_IT_wind007的博客-CSDN博客

自带的HeidiSQL工具觉得界面不太友好，于是自己下载了一个Navicat进行操作，相关操作参照以下连接文档：

Navicat使用快速入门教程_苜苜的烂笔头的博客-CSDN博客_navicat使用教程详解

以上步骤完成以后，打开C#工程，C#工程中的“引用”——添加——扩展——勾选MySql.Data，确认即可使用

在需要使用数据库操作的文件头添加  using MySql.Data.MySqlClient;

即可调用相关操作。

1、数据库连接

        public bool ConnectToSql()
        {

            // 对象转字符串方法
            MySqlConnectionStringBuilder builder = new MySqlConnectionStringBuilder();
            builder.Database = "plc_control";   // 数据库名
            builder.Server = "localhost";     // IP
            builder.Port = 3306;                // 端口号
            builder.UserID = "root";            // 用户名
            builder.Password = "root";          // 密码
            builder.CharacterSet = "utf8mb4";   // 编码格式

            if (null == conn)
            {
                conn = new MySqlConnection(builder.ToString());
            }

            try
            {
                conn.Open();

                //在open之后调用就可以避免creatTable报错
                MySqlCommand setcmd = new MySqlCommand("SET character_set_results=utf8mb4", conn);
                int n = setcmd.ExecuteNonQuery();
                setcmd.Dispose();

                Console.WriteLine("连接成功!!!");

                return true;
            }
            catch (Exception e1)
            {
                Console.WriteLine("打印抛出：" + e1.ToString() + builder.ToString());
                return false;
            }
        }

2、数据库关闭

    public void CloseConn()
        {
            if (null != conn)
            {
                if (conn.State == ConnectionState.Open)
                {
                    conn.Close();
                    Console.WriteLine("正常关闭!!!");
                }
            }
        }

3、创建（create table）

        private void CreatActionLogTable()
        {
            string strCreat = string.Format(@"CREATE TABLE IF NOT EXISTS actionlog(
                                  `time` datetime DEFAULT NULL,
                                  `user` varchar(24) DEFAULT NULL,
                                  `log` varchar(200) DEFAULT NULL
                                ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE utf8mb4_unicode_ci;");

            ExecuteQuery(strCreat);
        }


     private void ExecuteQuery(string strCreat)
        {
            try
            {
                MySqlCommand myCmd = new MySqlCommand(strCreat, conn);
                myCmd.ExecuteNonQuery();
            }
            catch (MySqlException ex) {
                Console.WriteLine("err:"+ex.Message);
            }
        }

4、增（insert）数据的批处理操作

　　　　　//插入指令的批处理操作
        public void ExecuteSqlTranssaction(List<string> sqlStrList)
        {
            //创建执行命令的command对象
            MySqlCommand command = new MySqlCommand();
            command.Connection = conn;

            //开启mysql事务
            MySqlTransaction transaction = conn.BeginTransaction();
            command.Transaction = transaction;

            try
            {

                if (sqlStrList.Count > 1)
                {
                    for (int i = 0; i < sqlStrList.Count; i++)
                    {
                        string sqlStr = sqlStrList[i].ToString();
                        if (sqlStr.Trim().Length > 1)
                        {
                            command.CommandText = sqlStr;
                            command.ExecuteNonQuery();
                        }

                        if (i > 0 && (i % 500 == 0
                            || i == sqlStrList.Count - 1))
                        {
                            transaction.Commit();

                            if (i != sqlStrList.Count - 1)
                            {
                                transaction = conn.BeginTransaction();
                            }
                        }
                    }
                }
                else
                {
                    for (int i = 0; i < sqlStrList.Count; i++)
                    {
                        string sqlStr = sqlStrList[i].ToString();
                        if (sqlStr.Trim().Length > 1)
                        {
                            command.CommandText = sqlStr;
                            command.ExecuteNonQuery();

                            transaction.Commit();

                        }
                    }
                }
            }
            catch (MySqlException err)
            {

                Console.WriteLine("ExecuteSqlTranssaction error!!!" + err.ToString());

                transaction.Rollback();
                throw new Exception(err.Message);

            }
        }

        private void Insert2actionlog(C_ActionLog tmpActionLog)
        {
            string sqlStr = string.Format("insert into actionlog (time,user,log) " +
                           "values('{0}','{1}','{2}');",
                           tmpActionLog.dateTime,
                           tmpActionLog.user,
                           tmpActionLog.logInfo);

            Console.WriteLine(sqlStr);

            actSqlStrList.Add(sqlStr);
        }

5、删（delete） 整理碎片

　　　　//多条删除
        public int DeleteLog(DateTime sTime, DateTime endTime) {

            string startTimeStr = sTime.ToString();
            string endTimeStr = endTime.ToString();

            //需要挑选日期 
            string sqlStr = string.Format("DELETE FROM actionlog WHERE time BETWEEN '{0}' AND '{1}' LIMIT 10000;", startTimeStr, endTimeStr);

            ExecuteQuery(sqlStr);

            //刪除数据以后，整理碎片  大量数据才需要用到
            string alterStr = string.Format("alter table actionlog engine = innodb,ALGORITHM=INPLACE, LOCK=NONE;");
            ExecuteQuery(alterStr);

            return 0;
        }

6、查（select）

        //获取日志
        public void SelectLogFromSql(short timeFlag, DateTime sTime, DateTime eTime, out List<C_ActionLog> logList)
        {

            logList = new List<C_ActionLog>();

            string sqlStr = "SELECT * FROM actionlog ";
            string timeStr = "";
            string endStr = ";";
            string startTimeStr = sTime.ToString();
            string endTimeStr = eTime.ToString();
            if (1 == timeFlag)
            {//需要挑选日期 
                timeStr = string.Format("WHERE time BETWEEN '{0}' AND '{1}' ", startTimeStr, endTimeStr);

            }

            sqlStr += timeStr + endStr;

            Console.WriteLine(sqlStr);

            MySqlCommand command = new MySqlCommand(sqlStr, conn);
            MySqlDataReader reader = command.ExecuteReader();

            while (reader.Read())
            {
                C_ActionLog ectionLog = new C_ActionLog();

                ectionLog.dateTime = reader.GetDateTime("time");
                ectionLog.user = reader.GetString("user");
                ectionLog.logInfo = reader.GetString("log");

                logList.Add(ectionLog);
            }

            reader.Close();
        }

7、改（Update）

  updateStr = string.Format("UPDATE equipcraftconf SET id={0},craftName='{1}' WHERE staNo={2} AND craftNo={3};",
                    equipCraftConf.id,
                    equipCraftConf.craftInfo.craftName,
                    equipCraftConf.craftInfo.staNo,
                    equipCraftConf.craftInfo.craftNo          
                    );

 ExecuteQuery(updateStr);