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

namespace CameraErrorCheck
{
    /// <summary>
    /// 数据库查询帮助类
    /// </summary>
    public class CameraMySqlHelp
    {
        /// <summary>
        /// 数据库连接字符串
        /// </summary>
        public static string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["MySqlConnString"].ConnectionString;

        /// <summary>
        /// 执行查询语句，返回DataTable
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataTable</returns>
        public static DataTable QueryTable(string SQLString)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                var dt = new DataTable();
                try
                {
                    connection.Open();
                    MySqlDataAdapter command = new MySqlDataAdapter(SQLString, connection);
                    command.Fill(dt);
                }
                catch (Exception ex)
                {
                    throw new Exception(ex.Message);
                }
                finally
                {
                    if (connection.State == ConnectionState.Open)
                    {
                        connection.Close();
                        MySqlConnection.ClearPool(connection);//加入此行可释放连接
                        connection.Dispose();
                    }
                    GC.Collect();
                }
                return dt;
            }
        }

        /// <summary>
        /// 执行Sql并返回受影响行数
        /// </summary>
        /// <param name="SQLString">Sql语句</param>
        /// <param name="cmdParms">参数</param>
        /// <returns>受影响行数</returns>
        public static int Execute(string SQLString)//Execute(string sql,)
        {
            return ExecuteSql(SQLString);
        }

        /// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <returns>影响的记录数</returns>
        public static int ExecuteSql(string SQLString)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        int rows = cmd.ExecuteNonQuery();
                        return rows;
                    }
                    catch (Exception E)
                    {
                        connection.Close();
                        throw new Exception(E.Message);
                    }
                    finally
                    {
                        if (connection.State == ConnectionState.Open)
                        {
                            connection.Close();
                            MySqlConnection.ClearPool(connection);//加入此行可释放连接
                            connection.Dispose();
                        }
                        GC.Collect();
                    }
                }
            }
        }

        /// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">多条SQL语句</param>		
        public static bool ExecuteSqlTran(List<string> SQLStringList)
        {
            var _result = false;
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                connection.Open();
                MySqlCommand cmd = new MySqlCommand();
                cmd.Connection = connection;
                MySqlTransaction tx = connection.BeginTransaction();
                cmd.Transaction = tx;
                try
                {
                    foreach (var strSql in SQLStringList)
                    {
                        if (strSql.Trim().Length > 1)
                        {
                            cmd.CommandText = strSql;
                            cmd.ExecuteNonQuery();
                        }
                    }
                    tx.Commit();
                    _result = true;
                }
                catch (Exception E)
                {
                    tx.Rollback();
                }
                finally
                {
                    if (connection.State == ConnectionState.Open)
                    {
                        connection.Close();
                        MySqlConnection.ClearPool(connection);//加入此行可释放连接
                        connection.Dispose();
                    }
                    GC.Collect();
                }
            }
            return _result;
        }
    }
}