数据库操作代码

/***********************************************************************
 * 创建人：Devilhand
 * 创建时间：2010-3-4
 * 说明：数据库助手类
************************************************************************/
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;
using System.Configuration;
using System.Data;

namespace DAL
{
    public class SQLHelper
    {
        private static  SqlConnection conn = null;
        private static SqlCommand cmd = null;
        private static SqlDataAdapter sda = null;
        private static SqlDataReader sdr = null;
        public SQLHelper()
        {
            string connStr = ConfigurationSettings.AppSettings["connStr"];
            conn = new SqlConnection(connStr);
        }
        #region 打开连接
        /// <summary>
        /// 打开连接
        /// </summary>
        private static  void  GetCon()
        {

            try
            {
                if (conn.State == ConnectionState.Closed)
                {
                    conn.Open();
                }
            }
            catch (Exception ex)
            {
                
                throw(ex);
            }
        }
        #endregion

        #region 关闭连接
        /// <summary>
        /// 关闭连接
        /// </summary>
        private static  void CloseCon()
        {
            if (conn.State == ConnectionState.Open)
            {
                conn.Close();
            }
        }
        #endregion

        #region 执行sql语句或存储过程返回受影响的行数
        /// <summary>
        /// 执行sql语句或存储过程返回受影响的行数
        /// </summary>
        /// <param name="cmdText">sql语句或存储过程</param>
        /// <param name="ct">命令类型</param>
        /// <returns>返回受影响的行数</returns>
        protected static int ExecuteReturnRows(string cmdText,CommandType ct)
        {
            int res;
            try
            {
                GetCon();
                cmd = new SqlCommand(cmdText, conn);
                cmd.CommandType = ct;
                res = cmd.ExecuteNonQuery();
                return res;
            }
            catch (Exception ex)
            {
                throw (ex);
            }
            finally
            {
                cmd.Dispose();
                CloseCon();
            }
        }
        #endregion

        #region 执行sql语句或存储过程返回受影响的行数
      /// <summary>
      /// 执行sql语句或存储过程返回受影响的行数
      /// </summary>
      /// <param name="cmdText">sql语句或存储过程</param>
      /// <param name="paras">参数集合</param>
      /// <param name="ct">命令类型</param>
        /// <returns>返回受影响的行数</returns>       
        protected static int ExecuteReturnRows(string cmdText,SqlParameter[] paras,CommandType ct)
        {
            int res;
            try
            {
                GetCon();
                cmd = new SqlCommand(cmdText, conn);
                cmd.CommandType = ct;
                cmd.Parameters.AddRange(paras);
                res = cmd.ExecuteNonQuery();
                return res;
            }
            catch (Exception ex)
            {
                throw (ex);
            }
            finally
            {
                cmd.Dispose();
                CloseCon();
            }
        }
        #endregion

        #region 执行sql语句或存储过程返回一个数据表
        /// <summary>
        /// 执行sql语句或存储过程返回一个数据表
        /// </summary>
        /// <param name="cmdText">sql语句或存储过程</param>
        /// <param name="ct">命令类型</param>
        /// <returns>返回一个数据表</returns>
        protected static DataTable ExecuteReturnTable(string cmdText, CommandType ct)
        {
            try
            {               
                DataTable dt = new DataTable();
                GetCon();
                cmd = new SqlCommand(cmdText, conn);
                cmd.CommandType = ct;
                sdr = cmd.ExecuteReader();
                dt.Load(sdr);
                return dt;
            }
            catch (Exception ex)
            {

                throw (ex);
            }
            finally
            {
                cmd.Dispose();
                CloseCon();
            }
        }
        #endregion    

        #region 执行sql语句或存储过程返回一个数据表
        /// <summary>
        /// 执行sql语句或存储过程返回一个数据表
        /// </summary>
        /// <param name="cmdText">sql语句或存储过程</param>
        /// <param name="paras">参数集合</param>
        /// <param name="ct">命令类型</param>
        /// <returns>返回一个数据表</returns>
        protected static DataTable ExecuteReturnTable(string cmdText, SqlParameter[] paras, CommandType ct)
        {
            try
            {
                DataTable dt = new DataTable();
                GetCon();
                cmd = new SqlCommand(cmdText, conn);
                cmd.Parameters.AddRange(paras);
                cmd.CommandType = ct;
                sdr = cmd.ExecuteReader();
                dt.Load(sdr);
                return dt;
            }
            catch (Exception ex)
            {

                throw (ex);
            }
            finally
            {
                cmd.Dispose();
                CloseCon();
            }
        }
        #endregion  

        #region 执行sql语句或存储过程返回一个数据集
        /// <summary>
        /// 执行sql语句或存储过程返回一个数据集
        /// </summary>
        /// <param name="cmdText">sql语句或存储过程</param>
        /// <param name="ct">命令类型</param>
        /// <returns>返回一个数据集</returns>
        protected static DataSet ExecuteReturnDs(string cmdText, CommandType ct)
        {
            try
            {
                DataSet ds = new DataSet();
                GetCon();
                cmd = new SqlCommand(cmdText, conn);
                cmd.CommandType = ct;
                sda.SelectCommand = cmd;
                sda.Fill(ds);
                return ds;
            }
            catch (Exception ex)
            {

                throw (ex);
            }
            finally
            {
                cmd.Dispose();
                CloseCon();
            }
                       
        }
        #endregion

        #region 执行sql语句或存储过程返回一个数据集
        /// <summary>
        /// 执行sql语句或存储过程返回一个数据集
        /// </summary>
        /// <param name="cmdText">sql语句或存储过程</param>
        /// <param name="paras">参数集合</param>
        /// <param name="ct">命令类型</param>
        /// <returns></returns>
        protected static DataSet ExecuteReturnDs(string cmdText, SqlParameter[] paras, CommandType ct)
        {
            try
            {
                DataSet ds = new DataSet();
                GetCon();
                cmd = new SqlCommand(cmdText, conn);
                cmd.CommandType = ct;
                cmd.Parameters.AddRange(paras);
                sda.SelectCommand = cmd;
                sda.Fill(ds);
                return ds;
            }
            catch (Exception ex)
            {

                throw (ex);
            }
            finally
            {
                cmd.Dispose();
                CloseCon();
            }
                       
        }
        #endregion

        #region 执行sql语句或存储过程返回第一个单元格
        /// <summary>
        /// 执行sql语句或存储过程返回第一个单元格
        /// </summary>
        /// <param name="cmdText">sql语句胡存储过程</param>
        /// <param name="ct">命令类型</param>
        /// <returns>返回第一个单元格</returns>
        protected static string ExecuteReturnFirstCell(string cmdText, CommandType ct)
        {
            try
            {
                GetCon();
                cmd = new SqlCommand(cmdText, conn);
                cmd.CommandType = ct;
                string res = Convert.ToString(cmd.ExecuteScalar());
                return res;

            }
            catch (Exception ex)
            {
                throw (ex);
            }
            finally
            {
                cmd.Dispose();
                CloseCon();
            }
        }
        #endregion

        #region 执行sql语句或存储过程返回第一个单元格
        /// <summary>
        /// 执行sql语句或存储过程返回第一个单元格
        /// </summary>
        /// <param name="cmdText">sql语句或存储过程</param>
        /// <param name="paras">参数集合</param>
        /// <param name="ct">命令类型</param>
        /// <returns>返回第一个单元格</returns>
        protected static string ExecuteReturnFirstCell(string cmdText, SqlParameter[] paras, CommandType ct)
        {
            try
            {
                GetCon();
                cmd = new SqlCommand(cmdText, conn);
                cmd.CommandType = ct;
                cmd.Parameters.AddRange(paras);
                string res = Convert.ToString (cmd.ExecuteScalar());
                return res;

            }
            catch (Exception ex)
            {
                throw (ex);
            }
            finally
            {
                cmd.Dispose();
                CloseCon();
            }
        }
        #endregion
    }
}