using MySql.Data.MySqlClient;
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace MonitoringTechnology.DataAccess
{
    //用于对数据库的操作
    public class LocalDataAccess
    {
        private static LocalDataAccess instance;
        public LocalDataAccess() { }
        public static LocalDataAccess GetInstance()
        {
            return instance ?? (instance = new LocalDataAccess());
        }


        //创建数据库相关的连接变量
        MySqlConnection conn;
        MySqlCommand comm;
        MySqlDataAdapter adapter;

        //统一的数据库操作完成的结束方法
        private void Dispose()
        {
            if (adapter != null)
            {
                adapter.Dispose();
                adapter = null;
            }
            if (comm != null)
            {
                comm.Dispose();
                comm = null;
            }
            if (conn != null)
            {
                conn.Close();
                conn.Dispose();
                conn = null;
            }
        }

        //统一的全局数据库连接
        private bool DBConnection()
        {
            //从资源文件中获取名字为“db”的数据库连接信息
            string connStr = ConfigurationManager.ConnectionStrings["db"].ToString();
            if (conn == null)
                conn = new MySqlConnection(connStr);
            try
            {
                conn.Open();
                return true;
            }
            catch (Exception)
            {
                return false;
            }
        }
        public void write(string sql)
        {
            if (DBConnection())
            {
                MySqlCommand t1 = new MySqlCommand(sql, conn);
                try
                {
                    if (t1.ExecuteNonQuery() > 0)
                    {
                        // Console.WriteLine("数据插入成功了！");
                    }
                }
                catch (Exception err)
                {
                    Console.WriteLine(err.Message);

                }
                finally
                {
                    this.Dispose();
                }
            }
        }
    }
}