using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
/*********************************
 * 类名：DBHelper
 * 功能描述：提供基本数据访问功能
 * ******************************/
namespace HotelManager.DAL
{
    public static class DBHelper
    {
        //数据库连接属性
        private static SqlConnection connection;
        public static SqlConnection Connection
        {
            get
            {
                string connectionString = ConfigurationManager.ConnectionStrings["HotelManageConnectionString"].ConnectionString;
                if (connection == null)
                {
                    connection = new SqlConnection(connectionString);
                    connection.Open();
                }
                else if (connection.State == System.Data.ConnectionState.Closed)
                {
                    connection.Open();
                }
                else if (connection.State == System.Data.ConnectionState.Broken)
                {
                    connection.Close();
                    connection.Open();
                }
                return connection;
            }
        }
        /// <summary>
        /// 执行无参SQL语句
        /// </summary>
        public static int ExecuteCommand(string safeSql)
        {
            SqlCommand cmd = new SqlCommand(safeSql, Connection);
            int result = cmd.ExecuteNonQuery();
            return result;
        }
        /// <summary>
        /// 执行带参SQL语句
        /// </summary>
         public static int ExecuteCommand(string sql, params SqlParameter[] values)
        {
            SqlCommand cmd = new SqlCommand(sql, Connection);
            cmd.Parameters.AddRange(values);
            return cmd.ExecuteNonQuery();
        }
        /// <summary>
        /// 执行无参SQL语句，并返回执行记录数
        /// </summary>
        public static int GetScalar(string safeSql)
        {
            SqlCommand cmd = new SqlCommand(safeSql, Connection);
            int result = Convert.ToInt32(cmd.ExecuteScalar());
            return result;
        }
        /// <summary>
        /// 执行有参SQL语句，并返回执行记录数
        /// </summary>
        public static int GetScalar(string sql, params SqlParameter[] values)
        {
            SqlCommand cmd = new SqlCommand(sql, Connection);
            cmd.Parameters.AddRange(values);
            int result = Convert.ToInt32(cmd.ExecuteScalar());
            return result;
        }
        /// <summary>
        /// 执行无参SQL语句，并返回SqlDataReader
        /// </summary>
        public static SqlDataReader GetReader(string safeSql)
        {
            SqlCommand cmd = new SqlCommand(safeSql, Connection);
            SqlDataReader reader = cmd.ExecuteReader();
            return reader;
        }
        /// <summary>
        /// 执行有参SQL语句，并返回SqlDataReader
        /// </summary>
        public static SqlDataReader GetReader(string sql, params SqlParameter[] values)
        {
            SqlCommand cmd = new SqlCommand(sql, Connection);
            cmd.Parameters.AddRange(values);
            SqlDataReader reader = cmd.ExecuteReader();
            return reader;
        }   
    }
}