数据访问基础类(基于Access数据库)

using System;
using System.Collections;
using System.Collections.Specialized;
using System.Data;
using System.Data.OleDb;
using System.Configuration;
using System.Data.Common;

namespace DataBase
{
    /// <summary>
    /// 数据访问基础类(基于Access数据库)
    /// </summary>
   public class OleDbHelper
    {
       protected static string connectionString = ConfigurationManager.ConnectionStrings["Connection"].ConnectionString;
       /// <summary>
       /// 默认构造函数；
       /// </summary>
       public OleDbHelper()
        {

        }
        #region  执行简单SQL语句
        /// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <returns>影响的记录数</returns>
        public int ExecuteSql(string SQLString)
        {
            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                using (OleDbCommand cmd = new OleDbCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        int rows = cmd.ExecuteNonQuery();
                        return rows;
                    }
                    catch (OleDbException ex)
                    {
                        connection.Close();
                        connection.Dispose();
                        log4net.ILog log = log4net.LogManager.GetLogger("File");
                        log.Debug(ex);
                        throw ex;
                    }
                }
            }
        }

        /// <summary>
        /// 执行多条SQL语句，实现数据库事务;
        /// </summary>
        /// <param name="SQLStringList">多条SQL语句;</param>        
        ///<returns>成功返回true,否则返回false;</returns>
        public bool ExecuteSqlTransaction(ArrayList SQLStringList)
        {
            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                using (OleDbCommand cmd = new OleDbCommand())
                {
                    connection.Open();
                    cmd.Connection = connection;
                    OleDbTransaction tx = connection.BeginTransaction();
                    cmd.Transaction = tx;
                    try
                    {
                        for (int n = 0; n < SQLStringList.Count; n++)
                        {
                            string strsql = SQLStringList[n].ToString();
                            if (strsql.Trim().Length > 1)
                            {
                                cmd.CommandText = strsql;
                                cmd.ExecuteNonQuery();
                            }
                        }
                        tx.Commit();
                        return true;
                    }
                    catch (OleDbException ex)
                    {
                        tx.Rollback();
                        connection.Close();
                        connection.Dispose();
                        log4net.ILog log = log4net.LogManager.GetLogger("File");
                        log.Debug(ex);
                        throw ex;
                    }
                }
            }
        }
        /// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <returns>查询结果（object）</returns>
        public object GetScalar(string SQLString)
        {
            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                using (OleDbCommand cmd = new OleDbCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        object obj = cmd.ExecuteScalar();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (OleDbException ex)
                    {
                        connection.Close();
                        connection.Dispose();
                        log4net.ILog log = log4net.LogManager.GetLogger("File");
                        log.Debug(ex);
                        throw ex;
                    }
                }
            }
        }
        /// <summary>
        /// 执行查询语句，返回OleDbDataReader,需要自己关闭DataReader
        /// </summary>
        /// <param name="strSQL">查询语句</param>
        /// <returns>OleDbDataReader</returns>
        public OleDbDataReader GetReader(string strSQL)
        {
            OleDbConnection connection = new OleDbConnection(connectionString);
            OleDbCommand cmd = new OleDbCommand(strSQL, connection);
            try
            {
                connection.Open();
                OleDbDataReader reader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                return reader;
            }
            catch (OleDbException ex)
            {
                connection.Close();
                connection.Dispose();
                log4net.ILog log = log4net.LogManager.GetLogger("File");
                log.Debug(ex);
                throw ex;
            }
        }
        /// <summary>
        /// 执行查询语句，返回DataSet
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataSet</returns>
        public DataSet GetDataSet(string SQLString)
        {
            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    OleDbDataAdapter adapter = new OleDbDataAdapter(SQLString, connection);
                    adapter.Fill(ds, "ds");
                    connection.Close();
                    return ds;
                }
                catch (OleDbException ex)
                {
                    connection.Close();
                    connection.Dispose();
                    log4net.ILog log = log4net.LogManager.GetLogger("File");
                    log.Debug(ex);
                    throw ex;
                }
            }
        }
        #endregion

        #region 执行带参数的SQL语句
        /// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <param name="cmdParms">参数列表</param>
        /// <returns>影响的记录数</returns>
        public int ExecuteSql(string SQLString, DbParameter[] cmdParms)
        {
            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                using (OleDbCommand cmd = new OleDbCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                        int rows = cmd.ExecuteNonQuery();
                        cmd.Parameters.Clear();
                        return rows;
                    }
                    catch (OleDbException ex)
                    {
                        connection.Close();
                        connection.Dispose();
                        log4net.ILog log = log4net.LogManager.GetLogger("File");
                        log.Debug(ex);
                        throw ex;
                    }
                }
            }
        }

        /// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">SQL语句的哈希表（key是该语句的SqlParameter[]，value为sql语句）</param>
        ///<returns >如果成功返回true,否则返回false;</returns>
        public bool ExecuteSqlTransaction(Hashtable SQLStringList)
        {
            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                connection.Open();
                using (OleDbTransaction trans = connection.BeginTransaction())
                {
                    OleDbCommand cmd = new OleDbCommand();
                    try
                    {
                        //循环
                        foreach (DictionaryEntry myDE in SQLStringList)
                        {
                            string cmdText = myDE.Value.ToString();
                            OleDbParameter[] cmdParms = (OleDbParameter[])myDE.Key;
                            PrepareCommand(cmd, connection, trans, cmdText, cmdParms);
                            int val = cmd.ExecuteNonQuery();
                            cmd.Parameters.Clear();
                        }
                        trans.Commit();
                        return true;
                    }
                    catch(OleDbException ex)
                    {
                        trans.Rollback();
                        connection.Close();
                        connection.Dispose();
                        log4net.ILog log = log4net.LogManager.GetLogger("File");
                        log.Debug(ex);
                        throw ex;
                    }
                }
            }
        }

        /// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）,返回首行首列的值;
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <param name="cmdParms">参数列表</param>
        /// <returns>查询结果（object）</returns>
        public object GetScalar(string SQLString, DbParameter[] cmdParms)
        {
            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                using (OleDbCommand cmd = new OleDbCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                        object obj = cmd.ExecuteScalar();
                        cmd.Parameters.Clear();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (OleDbException ex)
                    {
                        connection.Close();
                        connection.Dispose();
                        log4net.ILog log = log4net.LogManager.GetLogger("File");
                        log.Debug(ex);
                        throw ex;
                    }
                }
            }
        }

        /// <summary>
        /// 执行查询语句，返回OleDbDataReader
        /// </summary>
        /// <param name="SQLString">查询语句</param>
       /// <param name="cmdParms">参数列表</param>
        /// <returns>OleDbDataReader</returns>
        public OleDbDataReader GetReader(string SQLString, DbParameter[] cmdParms)
        {
            OleDbConnection connection = new OleDbConnection(connectionString);
            OleDbCommand cmd = new OleDbCommand();
            try
            {
                PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                OleDbDataReader reader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                cmd.Parameters.Clear();
                return reader;
            }
            catch (OleDbException  ex)
            {
                connection.Close();
                connection.Dispose();
                log4net.ILog log = log4net.LogManager.GetLogger("File");
                log.Debug(ex);
                throw ex;
            }
        }

        /// <summary>
        /// 执行查询语句，返回DataSet
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <param name="cmdParms">参数列表</param>
        /// <returns>DataSet</returns>
        public DataSet GetDataSet(string SQLString, DbParameter[] cmdParms)
        {
            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                OleDbCommand cmd = new OleDbCommand();
                PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                using (OleDbDataAdapter da = new OleDbDataAdapter(cmd))
                {
                    DataSet ds = new DataSet();
                    try
                    {
                        da.Fill(ds, "ds");
                        cmd.Parameters.Clear();
                        return ds;
                    }
                    catch (OleDbException ex)
                    {
                        connection.Close();
                        connection.Dispose();
                        log4net.ILog log = log4net.LogManager.GetLogger("File");
                        log.Debug(ex);
                        throw ex;
                    }
                }
            }
        }
        /// <summary>
        /// 初始Command
        /// </summary>
        /// <param name="cmd">Command对象</param>
        /// <param name="conn">数据库链接；</param>
        /// <param name="trans">事务对象</param>
        /// <param name="cmdText">SQL语句</param>
        /// <param name="cmdParms">参数</param>
        private void PrepareCommand(OleDbCommand cmd, OleDbConnection conn, OleDbTransaction trans, string cmdText, DbParameter[] cmdParms)
        {
            if (conn.State != ConnectionState.Open)
            {
                conn.Open();
            }
            cmd.Connection = conn;
            cmd.CommandText = cmdText;
            if (trans != null)
            {
                cmd.Transaction = trans;
            }
            cmd.CommandType = CommandType.Text;//cmdType;
            if (cmdParms != null)
            {
                foreach (OleDbParameter parm in cmdParms)
                {
                    cmd.Parameters.Add(parm);
                }
            }
        }
        #endregion
    }
}