using System;
using System.Data;
using System.Data.OleDb;

namespace dbControlDemo
{

    public class dbControl
    {
        private string _database;
        public string DataBase()//返回数据库名称
        {
            return this._database;
        }

        OleDbConnection Conn;

        public dbControl(string DataBase)
        {
            //
            // TODO: 在此处添加构造函数逻辑
            //
            this._database = DataBase;
            Conn = new OleDbConnection();
            Conn.ConnectionString = "Provider = Microsoft.Jet.OLEDB.4.0;Data Source ="+this._database;
        }

        //返回DataReader
        public OleDbDataReader getDataReader(string sql)
        {
            this.CheckConnection();
            OleDbDataReader dr = null;

            try
            {
                OleDbCommand dc = new OleDbCommand(sql,Conn);        
                dr = dc.ExecuteReader();    
            }
            catch(OleDbException oe)
            {
                throw new Exception("您在执行Sql语句："+sql.ToString()+"发生异常。读取数据库出现错误！",oe);
            }
            return dr;
            this.Close();
        }

        //没有返回值，执行数据库操作
        public void Execute(string sql)
        {
            this.CheckConnection();
            try
            {
                OleDbCommand dc = new OleDbCommand(sql,Conn);
                dc.ExecuteNonQuery();
            }
            catch(OleDbException oe)
            {
                throw new Exception("您在执行Sql语句："+sql.ToString()+"发生异常。执行数据库操作出现错误！",oe);
            }
            this.Close();
        }

        private void CheckConnection()
        {
            try
            {
                if (Conn.State != ConnectionState.Open)
                    Conn.Open();
            }
            catch (OleDbException oe)
            {
                throw new Exception("打开数据库联接错误！", oe);
            }
        }
        public void Close()
        {
            try
            {
                if (Conn.State == ConnectionState.Open)
                {
                    Conn.Close();
                }
            }
            catch(Exception e){
                throw new Exception("数据库关闭错误！",e);
            }
        }

    }
}