三层下面的sqlhelp

using System;
using System.Data;
using System.Data.SqlClient;
using System.Data.Odbc;
using System.Configuration;
using System.Collections;

    /// <summary>
    /// SQLHelper 的摘要说明。
    /// 提供多种数据执行方法,支持存储过程的使用
    ////// Ver:V1.1
    /// </summary>
    public abstract class SQLHelper
    {

        private static SqlConnection conn; //创建连接对象
        //数据库连接字符串,从web.config文件中读取数据库连接信息(此方法已经过期)
        public static readonly string CONN_STRING_NON_DTC = ConfigurationSettings.AppSettings["SQLDAL"];
        //public static readonly string CONN_STRING_NON_DTC = System.Configuration.ConfigurationManager.ConnectionStrings["SQLConnString"].ConnectionString;
        //参数缓存
        private static Hashtable parmCache=Hashtable.Synchronized(new Hashtable());
        ///<summary>
        ///ExcuteNonQuery命令通常用于执行数据库更新、删除、添加数据的操作，返回受影响的行数
        ///也可以用于返回存储过程的输出参数
        ///</summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(string connString,CommandType cmdType,string cmdText,params SqlParameter[] cmdParams)
        {
            SqlCommand cmd=new SqlCommand();
            using (SqlConnection conn=new SqlConnection(connString))
            {
                PrepareCommand(cmd,conn,null,cmdType,cmdText,cmdParams);
                int val=cmd.ExecuteNonQuery();
                cmd.Parameters.Clear();
                return val;
            }
        }
        ///<summary>
        ///ExcuteNonQuery命令通常用于执行数据库更新、删除、添加数据的操作，返回受影响的行数
        ///也可以用于返回存储过程的输出参数
        ///</summary>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(CommandType cmdType,string cmdText,params SqlParameter[] cmdParams)
        {
            SqlCommand cmd=new SqlCommand();
            using (SqlConnection conn=new SqlConnection(CONN_STRING_NON_DTC))
            {
                PrepareCommand(cmd,conn,null,cmdType,cmdText,cmdParams);
                int val=cmd.ExecuteNonQuery();
                cmd.Parameters.Clear();
                return val;
            }
        }
        ///<summary>
        ///ExcuteNonQuery命令通常用于执行数据库更新、删除、添加数据的操作，返回受影响的行数
        ///也可以用于返回存储过程的输出参数
        ///</summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="conn">an existing database connection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(SqlConnection conn, CommandType cmdType, string cmdText, params SqlParameter[] cmdParms) 
        {
            SqlCommand cmd = new SqlCommand();

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

        /// <summary>
        /// ExcuteNonQuery命令通常用于执行数据库更新、删除、添加数据的操作，返回受影响的行数
        /// 也可以用于返回存储过程的输出参数
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="trans">an existing sql transaction</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>an int representing the number of rows affected by the command</returns>
        public static int ExecuteNonQuery(SqlTransaction trans, CommandType cmdType, string cmdText, params SqlParameter[] cmdParms) 
        {
            int val=0;
            SqlCommand cmd = new SqlCommand();
            PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, cmdParms);
            val = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
            return val;
        }

        /// <summary>
        /// ExecuteReader用于返回SqlDataReader对象，该对象包含由某一命令返回的结果集
        /// 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  SqlDataReader r = ExecuteReader(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="connectionString">a valid connection string for a SqlConnection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>A SqlDataReader containing the results</returns>
        public static SqlDataReader ExecuteReader(string connString, CommandType cmdType, string cmdText, params SqlParameter[] cmdParms) 
        {
            SqlCommand cmd = new SqlCommand();
            conn = new SqlConnection(connString);
            try 
            {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
                SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                cmd.Parameters.Clear();
                return rdr;
            }
            catch {conn.Close();throw;}
        }
        /// <summary>
        /// ExecuteReader用于返回SqlDataReader对象，该对象包含由某一命令返回的结果集
        /// </summary>
        /// <returns>A SqlDataReader containing the results</returns>
        public static SqlDataReader ExecuteReader( CommandType cmdType, string cmdText, params SqlParameter[] cmdParms) 
        {
            SqlCommand cmd = new SqlCommand();
            conn = new SqlConnection(CONN_STRING_NON_DTC);
            try 
            {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
                SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                cmd.Parameters.Clear();
                return rdr;
            }
            catch {conn.Close();throw;}
        }
        
        /// <summary>
        /// ExecuteScalar方法用于返回一个值，该值始终是该命令返回的第一行第一列
        /// 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns>
        public static object ExecuteScalar( CommandType cmdType, string cmdText, params SqlParameter[] cmdParms) 
        {
            SqlCommand cmd = new SqlCommand();

            using (SqlConnection conn = new SqlConnection(CONN_STRING_NON_DTC)) 
            {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
                object val = cmd.ExecuteScalar();
                cmd.Parameters.Clear();
                return val;
            }
        }

        /// <summary>
        /// ExecuteScalar方法用于返回一个值，该值始终是该命令返回的第一行第一列
        /// 
        /// </summary>
        /// <remarks>
        /// e.g.:  
        ///  Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
        /// </remarks>
        /// <param name="conn">an existing database connection</param>
        /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param>
        /// <param name="commandText">the stored procedure name or T-SQL command</param>
        /// <param name="commandParameters">an array of SqlParamters used to execute the command</param>
        /// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns>
        public static object ExecuteScalar(SqlConnection conn, CommandType cmdType, string cmdText, params SqlParameter[] cmdParms) 
        {
            
            SqlCommand cmd = new SqlCommand();
            PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
            object val = cmd.ExecuteScalar();
            cmd.Parameters.Clear();
            return val;
        }

                /// <summary>
        /// ExecuteDataTable用户返回一个数据表格
        /// </summary>
        /// <param name="cmdType"></param>
        /// <param name="cmdText"></param>
        /// <param name="cmdParms"></param>
        /// <param name="dataSet"></param>
        /// <param name="tableName"></param>
        /// <returns></returns>
        public static DataTable ExecuteDataTable(CommandType cmdType,string cmdText,DataSet dataSet,string tableName,params SqlParameter[] cmdParms)
        {
            SqlCommand cmd=new SqlCommand();
            conn =new SqlConnection(CONN_STRING_NON_DTC);
            PrepareCommand(cmd,conn,null,cmdType,cmdText,cmdParms);
            SqlDataAdapter adapter=new SqlDataAdapter(cmd);
            if(dataSet==null)   
            dataSet   =   new   DataSet();   
            adapter.Fill(   dataSet   );   
            DataTable   dataTable   =   dataSet.Tables[dataSet.Tables.Count   -   1];   
            if   (   tableName   !=   null   )   
            dataTable.TableName   =   tableName;   
            return   dataTable;   

        }
        
        /// <summary>
        /// ExecuteDataTable用户返回一个数据表格
        /// </summary>
        /// <param name="cmdType"></param>
        /// <param name="cmdText"></param>
        /// <param name="cmdParms"></param>
        /// <param name="dataSet"></param>
        /// <param name="startRecord"></param>
        /// <param name="maxRecords"></param>
        /// <param name="tableName"></param>
        /// <returns></returns>
        public static DataTable ExecuteDataTable(CommandType cmdType,string cmdText,DataSet dataSet,int startRecord,int maxRecords,string tableName,params SqlParameter[] cmdParms)
        {
            SqlCommand cmd=new SqlCommand();
            conn =new SqlConnection(CONN_STRING_NON_DTC);
            PrepareCommand(cmd,conn,null,cmdType,cmdText,cmdParms);
            SqlDataAdapter adapter=new SqlDataAdapter(cmd);
            if(dataSet==null)   
            dataSet   =   new   DataSet();   
            adapter.Fill(dataSet,startRecord,maxRecords,tableName);
            DataTable   dataTable   =   dataSet.Tables[dataSet.Tables.Count   -   1];   
            if   (   tableName   !=   null   )   
            dataTable.TableName   =   tableName;   
            return   dataTable;   
        }

        /// <summary>
        /// ExecuteDataSet方法用于返回一个数据集
        /// </summary>
        /// <param name="connString"></param>
        /// <param name="cmdType"></param>
        /// <param name="cmdText"></param>
        /// <param name="srcTable"></param>
        /// <param name="cmdParms"></param>
        /// <returns></returns>
        public static DataSet ExecuteDataSet(string connString,CommandType cmdType,string cmdText,string srcTable,params SqlParameter[] cmdParms)
        {
            SqlCommand cmd=new SqlCommand();
            DataSet ds=new DataSet();
            conn =new SqlConnection(connString);
            PrepareCommand(cmd,conn,null,cmdType,cmdText,cmdParms);
            SqlDataAdapter adapter=new SqlDataAdapter(cmd);
            adapter.Fill(ds,srcTable);
            return ds;

        }
        /// <summary>
        /// ExecuteDataAdapter方法用于返回一个数据适配器
        /// </summary>
        /// <param name="connString"></param>
        /// <param name="cmdType"></param>
        /// <param name="cmdText"></param>
        /// <param name="cmdParms"></param>
        /// <returns></returns>
        public static SqlDataAdapter ExecuteDataAdapter(string connString,CommandType cmdType,string cmdText,params SqlParameter[] cmdParms)
        {
            SqlCommand cmd=new SqlCommand();
            conn =new SqlConnection(connString);
            PrepareCommand(cmd,conn,null,cmdType,cmdText,cmdParms);
            SqlDataAdapter adapter=new SqlDataAdapter(cmd);
            return adapter;    
         }
        /// <summary>
        /// 添加一个参数到缓存当中
        /// </summary>
        /// <param name="cacheKey">Key to the parameter cache</param>
        /// <param name="cmdParms">an array of SqlParamters to be cached</param>
        public static void CacheParameters(string cacheKey, params SqlParameter[] cmdParms) 
        {
            parmCache[cacheKey] = cmdParms;
        }

        /// <summary>
        /// GetCachedParameters用于返回command的参数数组，将输入的字符串转换为command的参数类型
        /// </summary>
        /// <param name="cacheKey">key used to lookup parameters</param>
        /// <returns>Cached SqlParamters array</returns>
        public static SqlParameter[] GetCachedParameters(string cacheKey) 
        {
            SqlParameter[] cachedParms = (SqlParameter[])parmCache[cacheKey];
            
            if (cachedParms == null)
                return null;
            
            SqlParameter[] clonedParms = new SqlParameter[cachedParms.Length];

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

            return clonedParms;
        }
        /// <summary>
        /// 关闭数据库连接
        /// </summary>
        public static void closeConn(){ conn.Close();}
        /// <summary>
        /// PrepareCommand方法不返回值，只是为即将要执行的command做一系列准备（打开数据库，定义连接，定义命令类型，定义命令事务）
        /// </summary>
        /// <param name="cmd">SqlCommand object</param>
        /// <param name="conn">SqlConnection object</param>
        /// <param name="trans">SqlTransaction object</param>
        /// <param name="cmdType">Cmd type e.g. stored procedure or text</param>
        /// <param name="cmdText">Command text, e.g. Select * from Products</param>
        /// <param name="cmdParms">SqlParameters to use in the command</param>
        private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, CommandType cmdType, string cmdText, SqlParameter[] 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 (SqlParameter parm in cmdParms)
                cmd.Parameters.Add(parm);
            }
        }
    }