using?System;
using?System.Collections.Generic;
using?System.Text;
using?System.Data.OleDb;
using?System.Data;

namespace?NJCS.Dal
{
????public?class?DBHelper
????{
????????private?static?OleDbConnection?connection;
????????public?static?OleDbConnection?Connection
????????{
????????????get
????????????{
????????????????string?connectionString?=?@“Provider=Microsoft.Jet.OLEDB.4.0;Data?Source=web/App_Data/njcs.mdb“;
????????????????if?（connection?==?null）
????????????????{
????????????????????connection?=?new?OleDbConnection（connectionString）;
????????????????????connection.Open（）;
????????????????}
????????????????else?if?（connection.State?==?System.Data.ConnectionState.Closed）
????????????????{
????????????????????connection.Open（）;
????????????????}
????????????????else?if?（connection.State?==?System.Data.ConnectionState.Broken）
????????????????{
????????????????????connection.Close（）;
????????????????????connection.Open（）;
????????????????}
????????????????return?connection;
????????????}
????????}


????????public?static?int?ExecuteCommand（string?safeSql）
????????{
????????????OleDbCommand?cmd?=?new?OleDbCommand（safeSql?Connection）;
????????????int?result?=?cmd.ExecuteNonQuery（）;
????????????return?result;
????????}

????????public?static?int?ExecuteCommand（string?sql?params?OleDbParameter[]?values）
????????{
????????????OleDbCommand?cmd?=?new?OleDbCommand（sql?Connection）;
????????????cmd.Parameters.AddRange（values）;
????????????return?cmd.ExecuteNonQuery（）;
????????}

????????public?static?int?GetScalar（string?safeSql）
????????{
????????????OleDbCommand?cmd?=?new?OleDbCommand（safeSql?Connection）;
????