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OleDbHelper.cs：源码内容
							﻿using System;
using System.Data;
using System.Data.Common;
using System.Text;
using System.Data.OleDb;
namespace DBUtility
{
    /// <summary>
    /// 数据库操作基类(for OleDb)
    /// </summary>
    internal class OleDbHelper : IDBHelper
    {
        /// <summary>
        /// 获取分页SQL
        /// </summary>
        /// <param name="tblName">表名</param>
        /// <param name="pageSize">每页显示条数</param>
        /// <param name="pageIndex">第几页</param>
        /// <param name="fldSort">排序字段（最后一个不需要填写正序还是倒序，例如：id asc, name）</param>
        /// <param name="fldDir">最后一个排序字段的正序或倒序（true为倒序，false为正序）</param>
        /// <param name="condition">条件</param>
        /// <returns>返回用于分页的SQL语句</returns>
        private string GetPagerSQL(string tblName, int pageSize, int pageIndex, string fldSort, bool fldDir, string condition)
        {
            string strDir = fldDir ? " ASC" : " DESC";
            if (pageIndex == 1)
            {
                return "select top " + pageSize.ToString() + " * from " + tblName.ToString()
                    + ((string.IsNullOrEmpty(condition)) ? string.Empty : (" where " + condition))
                    + " order by " + fldSort.ToString() + strDir;
            }
            else
            {
                StringBuilder strSql = new StringBuilder();
                strSql.AppendFormat("select top {0} * from {1} ", pageSize, tblName);
                strSql.AppendFormat(" where {1} not in (select top {0} {1} from {2} ", pageSize * (pageIndex - 1),
                    (fldSort.Substring(fldSort.LastIndexOf(',') + 1, fldSort.Length - fldSort.LastIndexOf(',') - 1)), tblName);
                if (!string.IsNullOrEmpty(condition))
                {
                    strSql.AppendFormat(" where {0} order by {1}{2}) and {0}", condition, fldSort, strDir);
                }
                else
                {
                    strSql.AppendFormat(" order by {0}{1}) ", fldSort, strDir);
                }
                strSql.AppendFormat(" order by {0}{1}", fldSort, strDir);
                return strSql.ToString();
            }
        }
        /// <summary>
        /// 分页获取数据
        /// </summary>
        /// <param name="connectionString">连接字符串</param>
        /// <param name="tblName">表名</param>
        /// <param name="fldName">字段名</param>
        /// <param name="pageSize">页大小</param>
        /// <param name="pageIndex">第几页</param>
        /// <param name="fldSort">排序字段</param>
        /// <param name="fldDir">升序{False}/降序(True)</param>
        /// <param name="condition">条件(不需要where)</param>
        public DbDataReader GetPageList(string connectionString, string tblName, int pageSize,
            int pageIndex, string fldSort, bool fldDir, string condition)
        {
            string sql = GetPagerSQL(tblName, pageSize, pageIndex, fldSort, fldDir, condition);
            return ExecuteReader(connectionString, CommandType.Text, sql, null);
        }
        /// <summary>
        /// 得到数据条数
        /// </summary>
        public int GetCount(string connectionString, string tblName, string condition)
        {
            StringBuilder sql = new StringBuilder("select count(*) from " + tblName);
            if (!string.IsNullOrEmpty(condition))
                sql.Append(" where " + condition);
            object count = ExecuteScalar(connectionString, CommandType.Text, sql.ToString(), null);
            return int.Parse(count.ToString());
        }
        /// <summary>
        /// 执行查询，返回DataSet
        /// </summary>
        public DataSet ExecuteQuery(string connectionString, CommandType cmdType, string cmdText,
            params DbParameter[] cmdParms)
        {
            using (OleDbConnection conn = new OleDbConnection(connectionString))
            {
                using (OleDbCommand cmd = new OleDbCommand())
                {
                    PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
                    using (OleDbDataAdapter da = new OleDbDataAdapter(cmd))
                    {
                        DataSet ds = new DataSet();
                        da.Fill(ds, "ds");
                        cmd.Parameters.Clear();
                        return ds;
                    }
                }
            }
        }
        /// <summary>
        /// 在事务中执行查询，返回DataSet
        /// </summary>
        public DataSet ExecuteQuery(DbTransaction trans, CommandType cmdType, string cmdText,
            params DbParameter[] cmdParms)
        {
            OleDbCommand cmd = new OleDbCommand();
            PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, cmdParms);
            OleDbDataAdapter da = new OleDbDataAdapter(cmd);
            DataSet ds = new DataSet();
            da.Fill(ds, "ds");
            cmd.Parameters.Clear();
            return ds;
        }
        /// <summary>
        /// 执行 Transact-SQL 语句并返回受影响的行数。
        /// </summary>
        public int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText,
            params DbParameter[] cmdParms)
        {
            OleDbCommand cmd = new OleDbCommand();
            using (OleDbConnection conn = new OleDbConnection(connectionString))
            {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
                int val = cmd.ExecuteNonQuery();
                cmd.Parameters.Clear();
                return val;
            }
        }
        /// <summary>
        /// 在事务中执行 Transact-SQL 语句并返回受影响的行数。
        /// </summary>
        public int ExecuteNonQuery(DbTransaction trans, CommandType cmdType, string cmdText,
            params DbParameter[] cmdParms)
        {
            OleDbCommand cmd = new OleDbCommand();
            PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, cmdParms);
            int val = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
            return val;
        }
        /// <summary>
        /// 执行查询，返回DataReader
        /// </summary>
        public DbDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText,
            params DbParameter[] cmdParms)
        {
            OleDbCommand cmd = new OleDbCommand();
            OleDbConnection conn = new OleDbConnection(connectionString);
            try
            {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
                OleDbDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                cmd.Parameters.Clear();
                return rdr;
            }
            catch
            {
                conn.Close();
                throw;
            }
        }
        /// <summary>
        /// 在事务中执行查询，返回DataReader
        /// </summary>
        public DbDataReader ExecuteReader(DbTransaction trans, CommandType cmdType, string cmdText,
            params DbParameter[] cmdParms)
        {
            OleDbCommand cmd = new OleDbCommand();
            PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, cmdParms);
            OleDbDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
            cmd.Parameters.Clear();
            return rdr;
        }
        /// <summary>
        /// 执行查询，并返回查询所返回的结果集中第一行的第一列。忽略其他列或行。
        /// </summary>
        public object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText,
            params DbParameter[] cmdParms)
        {
            OleDbCommand cmd = new OleDbCommand();
            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                PrepareCommand(cmd, connection, null, cmdType, cmdText, cmdParms);
                object val = cmd.ExecuteScalar();
                cmd.Parameters.Clear();
                return val;
            }
        }
        /// <summary>
        /// 在事务中执行查询，并返回查询所返回的结果集中第一行的第一列。忽略其他列或行。
        /// </summary>
        public object ExecuteScalar(DbTransaction trans, CommandType cmdType, string cmdText,
            params DbParameter[] cmdParms)
        {
            OleDbCommand cmd = new OleDbCommand();
            PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, cmdParms);
            object val = cmd.ExecuteScalar();
            cmd.Parameters.Clear();
            return val;
        }
        /// <summary>
        /// 生成要执行的命令
        /// </summary>
        private static void PrepareCommand(DbCommand cmd, DbConnection conn, DbTransaction trans, CommandType cmdType,
            string cmdText, DbParameter[] cmdParms)
        {
            if (conn.State != ConnectionState.Open)
                conn.Open();
            cmd.Connection = conn;
            cmd.CommandText = cmdText.Replace("?", "@").Replace(":", "@");
            if (trans != null)
                cmd.Transaction = trans;
            cmd.CommandType = cmdType;
            if (cmdParms != null)
            {
                foreach (OleDbParameter parm in cmdParms)
                {
                    parm.ParameterName = parm.ParameterName.Replace("?", "@").Replace(":", "@");
                    cmd.Parameters.Add(parm);
                }
            }
        }
    }
}

						