oracleHelper 操作帮助类

using System;
using System.Configuration;
using System.Data;
using System.Collections;
using Oracle.DataAccess.Client;

namespace Cont.DAL.Leave
{
    /// <summary>
    ///Oracle数据库操作帮助类
    /// </summary>
    public class OracleHelper
    {
        //从配置文件中读取配置好的连接字符串
        private static  OracleConnection conn = new OracleConnection(ConfigurationManager.ConnectionStrings["conn"].ToString());
        private static OracleTransaction tran = null;

        /// <summary>
        /// 返回受影响的行数
        /// </summary>
        /// <param name="sql">sql语句</param>
        /// <returns></returns>
        public static int NonQuery(string sql)
        {
            try
            {
                OracleCommand cmd = new OracleCommand(sql, conn);
                int i = cmd.ExecuteNonQuery();
                return i;//将受影响的行数返回
            }
            catch (Exception se)
            {
                throw se;
            }
          
        }
        /// <summary>
        /// 返回一个临时表数据，一般执行显示表中多条数据操作  select
        /// </summary>
        /// <param name="sql">要执行的查询sql语句</param>
        /// <returns>返回一个DataTable</returns>
        public static DataTable GetTable(string sql)
        {
            try
            {
                conn.Open();
                OracleDataAdapter sda = new OracleDataAdapter(sql, conn);
                DataTable dt = new DataTable();
                sda.Fill(dt);
                return dt;
            }
            catch (Exception se)
            {
                throw se;
            }
            finally
            {
                conn.Close();
            }

        }
        /// <summary>
        /// 执行查询操作，返回一个结果集
        /// </summary>
        /// <param name="sql">要执行的sql语句</param>
        /// <returns>返回一个读取器</returns>
        public static OracleDataReader Reader(string sql)
        {
            try
            {
                conn.Open();
                OracleCommand cmd = new OracleCommand(sql, conn);
                OracleDataReader sdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);//读取器和数据源此处不能被关闭
                return sdr;
            }
            catch (Exception se)
            {
                throw se;
            }
        }
        /// <summary>
        /// 执行查询操作，返回一个单值，一般执行根据名称找编号或执行聚合函数
        /// </summary>
        /// <param name="sql">要执行的sql查询语句</param>
        /// <returns>返回一个object类型</returns>
        public static object Scalar(string sql)
        {
            try
            {
                conn.Open();
                OracleCommand cmd = new OracleCommand(sql, conn);
                object obj = cmd.ExecuteScalar();
                return obj;
            }
            catch (Exception se)
            {
                throw se;
            }
            finally
            {
                conn.Close();
            }
        }

        /// <summary>
        ///开始事务 
        /// </summary>
        public static void BeginTran()
        {
            conn.Open();
            tran = conn.BeginTransaction();
        }

        /// <summary>
        /// 提交事务
        /// </summary>
        public static void CommitTran()
        {
            tran.Commit();
            tran.Dispose();
            conn.Close();
            tran = null;
        }

        /// <summary>
        /// 回滚
        /// </summary>
        public static void RollbackTran()
        {
            tran.Rollback();
            tran.Dispose();
            conn.Close();
            tran = null;
        }
    }
}