create table Survey
(
ID int identity Primary key not null ,
SurveyID varchar(20) default \"\" not null ,
Kind tinyint default 0 not null ,
Title nvarchar(100) default \"\" not null ,
Description nvarchar(255) default \"\" not null ,
Amount int default 0 not null ,
BeginTime datetime default getdate() not null ,
EndTime datetime default getdate() not null ,
Active bit default 0 not null
)
go

好了，数据库建好了，我可以从上面的survey基类中继承出具体的子类，比如说我现在要做一个同足球相

关的调查，那就做这么一个类：

namespace Football
{
using System;
using MyClass.Util ;
using System.Data.SQL ;
using System.Collections ;
/// <summary>
/// 足球舆论调查
/// </summary>
/// <remarks>
/// 从MyClass.Util.Survey类继承而来
/// </remarks>
public class FootballSurvey : MyClass.Util.Survey
{

public FootballSurvey()
{
}

/// <summary>
/// 重载父类虚函数
/// </summary>
/// <param name=\"a_intID\">该调查的数据库id </param>
public override void LoadFromDatabase(string a_strID)
{
MyClass.Util.MyConnection myConn = new MyConnection() ;
SQLCommand myCommand = new SQLCommand() ;
myCommand.CommandText = \"up_GetSurvey\" ;
myCommand.CommandType = System.Data.CommandType.StoredProcedure ;

try
{
myConn.Open() ;
myCommand.ActiveConnection = myConn ;
myCommand.Parameters.Add(new SQLParameter(\"@a_strsurveyid\" ,

SQLDataType.VarChar , 20)) ;
myCommand.Parameters[\"@a_strsurveyid\"].Value = a_strID ;
SQLDataReader myReader ;
myCommand.Execute(out myReader) ;

//先取调查
if (myReader.Read())
{
this.m_strTitle = myReader[\"title\"].ToString() ;
this.m_intHits = (int)myReader[\"amount\"] ;
this.m_strID = a_strID ;
this.m_datBeginTime =

(DateTime)myReader[\"begintime\"] ;
this.m_datEndTime = (DateTime)myReader[\"endtime\"] ;
}
else
{
throw(new Exception(\"数据库中无此调查的纪录\")) ;
}

//清空调查项
m_arrItems.Clear() ;

//取调查项
if (myReader.HasMoreRows)
{
while(myReader.Read())
{
SurveyItem item = new SurveyItem() ;
item.Text = myReader[\"title\"].ToString() ;
item.ID = (int)myReader[\"id\"] ;
item.Count = (int)myReader[\"amount\"] ;
item.Description =

myReader[\"Description\"].ToString() ;
AddItem(item) ;
}
}
else
{
throw(new Exception(\"数据库中没有该调查相关的调查项

\")) ;
}

//清场
myReader.Close() ;
myConn.Close() ;
}
catch(Exception e)
{
throw(new Exception(\"从数据库中读取调查失败：\" +

e.ToString())) ;
}
}

/// <summary>
/// 将调查保存到数据库
/// </summary>
/// <param name=\"m_strSurveyID\">调查编号 </param>
/// <remarks>
/// 如果m_strSurveyID不为空，则删除原纪录，用当前调查编号保存新的调查，
/// 否则就生成一个新的调查编号
/// </remarks>
public override void SaveToDatabase(string m_strSurveyID)
{
//如果没有标题或调查项则抛出异常
if (this.m_arrItems.Count == 0 || this.m_strTitle == \"\")
{
throw(new Exception(\"没有调查标题或标题项\")) ;
}

MyClass.Util.MyConnection myConn = new MyConnection() ;
SQLCommand myCommand = new SQLCommand() ;
myCommand.CommandType = System.Data.CommandType.Text ;

try
{
myConn.Open() ;
myCommand.ActiveConnection = myConn ;

//如果没有surveyid则生成surveyid
string strSurveyID ;
if(m_strSurveyID == \"\")
{
strSurveyID = DateTime.Now.Year.ToString()
+

DateTime.Now.Month.ToString()
+

DateTime.Now.Hour.ToString()
+

DateTime.Now.Minute.ToString()
+

DateTime.Now.Second.ToString()
+

DateTime.Now.Millisecond.ToString() ;
}
else //如果已有，则删除该条纪录
{
strSurveyID = m_strSurveyID ;
//删除原有纪录
myCommand.CommandText = \"delete from survey where

surveyid=\'\" + strSurveyID + \"\'\" ;
myCommand.ExecuteNonQuery() ;
}

string strSql = \"insert into survey(surveyid , kind , title)

values (\'\"
+ strSurveyID +\"\', 0 , \'\" +

m_strTitle + \"\')/r/n\" ;
for (int i = 0 ; i < m_arrItems.Count ; i ++)
{
strSql += \"insert into survey(surveyid , kind ,

title) values(\'\"
+ strSurveyID + \"\' , 1 , \'\"
+ ((SurveyItem)m_arrItems[i]).Text +

\"\')/r/n\" ;
}
//插库
myCommand.CommandText = strSql ;
myCommand.ExecuteNonQuery() ;

//清场
myConn.Close() ;
}
catch(Exception e)
{
throw(new Exception(\"保存调查时出错：\" + e.ToString())) ;
}

}

/// <summary>
/// 投票
/// </summary>
/// <param name=\"a_intID\"> </param>
public override void Vote(int a_intID)
{
//该项计数加一
((SurveyItem)m_arrItems[a_intID]).Count += 1 ;

//数据库中改变
MyConnection myConn = new MyConnection() ;
SQLCommand myCommand = new SQLCommand() ;
myCommand.CommandText = \"update survey set amount=amount+1 where

id=\"
+

((SurveyItem)m_arrItems[a_intID]).ID.ToString() ;

myCommand.CommandType = System.Data.CommandType.Text ;

try
{
myConn.Open() ;
myCommand.ActiveConnection = myConn ;
myCommand.ExecuteNonQuery() ;
myConn.Close() ;
}
catch(Exception e)
{
throw(new Exception(\"更新调查项失败:\" + e.ToString())) ;
}

}

/// <summary>
/// 调查列表
/// </summary>
public static ArrayList SurveyList()
{
ArrayList arrResult = new ArrayList() ;
MyClass.Util.MyConnection myConn = new MyConnection() ;
SQLCommand myCommand = new SQLCommand() ;
myCommand.CommandText = \"select id , surveyid , title from survey

where kind=0 order by surveyid desc\" ;
myCommand.CommandType = System.Data.CommandType.Text ;

try
{
myConn.Open() ;
myCommand.ActiveConnection = myConn ;
SQLDataReader myReader ;
myCommand.Execute(out myReader) ;
while (myReader.Read())
{
FootballSurvey mySurvey = new FootballSurvey() ;
mySurvey.Title = myReader[\"title\"].ToString() ;
mySurvey.SurveyID = myReader[\"surveyid\"].ToString()

;
arrResult.Add(mySurvey) ;
}

myReader.Close() ;
myConn.Close() ;

}
catch(Exception e)
{
throw(new Exception(\"从数据库中取出调查失败:\" +

e.ToString())) ;
}

//返回结果
return arrResult ;
}

/// <summary>
/// 取得激活的调查id
/// </summary>
public static string GetActiveSurveyID()
{
string strResult = \"\" ;

MyClass.Util.MyConnection myConn = new MyConnection() ;
SQLCommand myCommand = new SQLCommand() ;
myCommand.CommandText = \"select top 1 id , surveyid from survey

where active=1 order by id desc\" ;
myCommand.CommandType = System.Data.CommandType.Text ;

try
{
myConn.Open() ;
myCommand.ActiveConnection = myConn ;
SQLDataReader myReader ;
myCommand.Execute(out myReader) ;
if (myReader.Read())
{
strResult = myReader[\"surveyid\"].ToString() ;
}
else
{
throw(new Exception(\"没有激活的调查\")) ;
}

myReader.Close() ;

}
catch(Exception e)
{
throw(new Exception(\"从数据库中取出调查失败:\" +

e.ToString())) ;
}
finally
{
myConn.Close() ;
}

//返回结果
return strResult ;

}

/// <summary>
/// 激活调查
/// </summary>
/// <param name=\"a_strSurveyID\">调查编号 </param>
public static void ActiveSurvey(string a_strSurveyID)
{
MyClass.Util.MyConnection myConn = new MyClass.Util.MyConnection() ;
SQLCommand myCommand = new SQLCommand() ;
myCommand.CommandText = \"update survey set active=0 ;\"
+ \"update survey set

active=1 where surveyid=\'\" + a_strSurveyID + \"\'\" ;
myCommand.CommandType = System.Data.CommandType.Text ;

try
{
myConn.Open() ;
myCommand.ActiveConnection = myConn ;
myCommand.ExecuteNonQuery() ;
}
catch(Exception exp)
{
throw(new Exception(\"保存激活调查到数据库出错：\" +

exp.ToString()));
}
finally
{
myConn.Close() ;
}
}

}
}