using System;
using System.Collections;
using System.Configuration;
using MySql.Data;
using MySql.Data.MySqlClient;
using System.Data;

/// <summary>
///MYSQLHelper 的摘要說明
/// </summary>
public abstract class MySqlHelper
{
    //資料庫連線字串
    public static string Conn = "Database='你要輸入的資料庫名稱';Data Source='localhost';User Id='root';Password='你要輸入的密碼';charset='utf8';pooling=true"
 
;

    // 用於快取引數的HASH表
    private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable());

    /// <summary>
    ///  給定連線的資料庫用假設引數執行一個sql命令（不返回資料集）
    /// </summary>
    /// <param name="connectionString">一個有效的連線字串</param>
    /// <param name="cmdType">命令型別(儲存過程, 文字, 等等)</param>
 

    /// <param name="cmdText">儲存過程名稱或者sql命令語句</param>
    /// <param name="commandParameters">執行命令所用引數的集合</param>
    /// <returns>執行命令所影響的行數</returns>
    public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
    {

        MySqlCommand cmd = new
 
 MySqlCommand();

        using (MySqlConnection conn = new MySqlConnection(connectionString))
        {
            PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
            int val = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
            return val;
        }
    }

    /// <summary>
    /// 用現有的資料庫連線執行一個sql命令（不返回資料集）
    /// </summary>
    /// <param name="connection">一個現有的資料庫連線</param>
    /// <param name="cmdType">命令型別(儲存過程, 文字, 等等)</param>
    /// <param name="cmdText">儲存過程名稱或者sql命令語句</param>
    /// <param name="commandParameters">執行命令所用引數的集合</param>
    /// <returns>執行命令所影響的行數</returns>
    public static int ExecuteNonQuery(MySqlConnection connection, CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
    {

        MySqlCommand cmd = new MySqlCommand();

        PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
        int val = cmd.ExecuteNonQuery();
        cmd.Parameters.Clear();
        return val;
    }

    /// <summary>
    ///使用現有的SQL事務執行一個sql命令（不返回資料集）
    /// </summary>
    /// <remarks>
    ///舉例:
    ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
    /// </remarks>
    /// <param name="trans">一個現有的事務</param>
    /// <param name="cmdType">命令型別(儲存過程, 文字, 等等)</param>
    /// <param name="cmdText">儲存過程名稱或者sql命令語句</param>
    /// <param name="commandParameters">執行命令所用引數的集合</param>
    /// <returns>執行命令所影響的行數</returns>
    public static int ExecuteNonQuery(MySqlTransaction trans, CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
    {
        MySqlCommand cmd = new MySqlCommand();
        PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);
        int val = cmd.ExecuteNonQuery();
        cmd.Parameters.Clear();
        return val;
    }

    /// <summary>
    /// 用執行的資料庫連線執行一個返回資料集的sql命令
    /// </summary>
    /// <remarks>
    /// 舉例:
    ///  MySqlDataReader r = ExecuteReader(connString, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
    /// </remarks>
    /// <param name="connectionString">一個有效的連線字串</param>
    /// <param name="cmdType">命令型別(儲存過程, 文字, 等等)</param>
    /// <param name="cmdText">儲存過程名稱或者sql命令語句</param>
    /// <param name="commandParameters">執行命令所用引數的集合</param>
    /// <returns>包含結果的讀取器</returns>
    public static MySqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
    {
        //建立一個MySqlCommand物件
        MySqlCommand cmd = new MySqlCommand();
        //建立一個MySqlConnection物件
        MySqlConnection conn = new MySqlConnection(connectionString);

        //在這裡我們用一個try/catch結構執行sql文字命令/儲存過程，因為如果這個方法產生一個異常我們要關閉連線，因為沒有讀取器存在，
        //因此commandBehaviour.CloseConnection 就不會執行
        try
        {
            //呼叫 PrepareCommand 方法，對 MySqlCommand 物件設定引數
            PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
            //呼叫 MySqlCommand  的 ExecuteReader 方法
            MySqlDataReader reader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
            //清除引數
            cmd.Parameters.Clear();
            return reader;
        }
        catch
        {
            //關閉連線，丟擲異常
            conn.Close();
            throw;
        }
    }

    /// <summary>
    /// 返回DataSet
    /// </summary>
    /// <param name="connectionString">一個有效的連線字串</param>
    /// <param name="cmdType">命令型別(儲存過程, 文字, 等等)</param>
    /// <param name="cmdText">儲存過程名稱或者sql命令語句</param>
    /// <param name="commandParameters">執行命令所用引數的集合</param>
    /// <returns></returns>
    public static DataSet GetDataSet(string connectionString, CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
    {
        //建立一個MySqlCommand物件
        MySqlCommand cmd = new MySqlCommand();
        //建立一個MySqlConnection物件
        MySqlConnection conn = new MySqlConnection(connectionString);

        //在這裡我們用一個try/catch結構執行sql文字命令/儲存過程，因為如果這個方法產生一個異常我們要關閉連線，因為沒有讀取器存在，

        try
        {
            //呼叫 PrepareCommand 方法，對 MySqlCommand 物件設定引數
            PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
            //呼叫 MySqlCommand  的 ExecuteReader 方法
            MySqlDataAdapter adapter = new MySqlDataAdapter();
            adapter.SelectCommand = cmd;
            DataSet ds = new DataSet();

            adapter.Fill(ds);
            //清除引數
            cmd.Parameters.Clear();
            conn.Close();
            return ds;
        }
        catch (Exception e)
        {
            throw e;
        }
    }



    /// <summary>
    /// 用指定的資料庫連線字串執行一個命令並返回一個數據集的第一列
    /// </summary>
    /// <remarks>
    ///例如:
    ///  Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
    /// </remarks>
    ///<param name="connectionString">一個有效的連線字串</param>
    /// <param name="cmdType">命令型別(儲存過程, 文字, 等等)</param>
    /// <param name="cmdText">儲存過程名稱或者sql命令語句</param>
    /// <param name="commandParameters">執行命令所用引數的集合</param>
    /// <returns>用 Convert.To{Type}把型別轉換為想要的 </returns>
    public static object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
    {
        MySqlCommand cmd = new MySqlCommand();

        using (MySqlConnection connection = new MySqlConnection(connectionString))
        {
            PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
            object val = cmd.ExecuteScalar();
            cmd.Parameters.Clear();
            return val;
        }
    }

    /// <summary>
    /// 用指定的資料庫連線執行一個命令並返回一個數據集的第一列
    /// </summary>
    /// <remarks>
    /// 例如:
    ///  Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new MySqlParameter("@prodid", 24));
    /// </remarks>
    /// <param name="connection">一個存在的資料庫連線</param>
    /// <param name="cmdType">命令型別(儲存過程, 文字, 等等)</param>
    /// <param name="cmdText">儲存過程名稱或者sql命令語句</param>
    /// <param name="commandParameters">執行命令所用引數的集合</param>
    /// <returns>用 Convert.To{Type}把型別轉換為想要的 </returns>
    public static object ExecuteScalar(MySqlConnection connection, CommandType cmdType, string cmdText, params MySqlParameter[] commandParameters)
    {

        MySqlCommand cmd = new MySqlCommand();

        PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
        object val = cmd.ExecuteScalar();
        cmd.Parameters.Clear();
        return val;
    }

    /// <summary>
    /// 將引數集合新增到快取
    /// </summary>
    /// <param name="cacheKey">新增到快取的變數</param>
    /// <param name="commandParameters">一個將要新增到快取的sql引數集合</param>
    public static void CacheParameters(string cacheKey, params MySqlParameter[] commandParameters)
    {
        parmCache[cacheKey] = commandParameters;
    }

    /// <summary>
    /// 找回快取引數集合
    /// </summary>
    /// <param name="cacheKey">用於找回引數的關鍵字</param>
    /// <returns>快取的引數集合</returns>
    public static MySqlParameter[] GetCachedParameters(string cacheKey)
    {
        MySqlParameter[] cachedParms = (MySqlParameter[])parmCache[cacheKey];

        if (cachedParms == null)
            return null;

        MySqlParameter[] clonedParms = new MySqlParameter[cachedParms.Length];

        for (int i = 0, j = cachedParms.Length; i < j; i++)
            clonedParms[i] = (MySqlParameter)((ICloneable)cachedParms[i]).Clone();

        return clonedParms;
    }

    /// <summary>
    /// 準備執行一個命令
    /// </summary>
    /// <param name="cmd">sql命令</param>
    /// <param name="conn">OleDb連線</param>
    /// <param name="trans">OleDb事務</param>
    /// <param name="cmdType">命令型別例如 儲存過程或者文字</param>
    /// <param name="cmdText">命令文字,例如:Select * from Products</param>
    /// <param name="cmdParms">執行命令的引數</param>
    private static void PrepareCommand(MySqlCommand cmd, MySqlConnection conn, MySqlTransaction trans, CommandType cmdType, string cmdText, MySqlParameter[] cmdParms)
    {
        if (conn.State != ConnectionState.Open)
            conn.Open();
        cmd.Connection = conn;
        cmd.CommandText = cmdText;
        if (trans != null)
            cmd.Transaction = trans;
        cmd.CommandType = cmdType;
        if (cmdParms != null)
        {
            foreach (MySqlParameter parm in cmdParms)
                cmd.Parameters.Add(parm);
        }
    }
}