今天做项目中,写了个类,中间用于判断新闻是否存在。其中我的记录只有8条,Id分别为7,8,9,10,11,12,13,14,当用sql语句: private const string SQL_SELECT_COUNT_ID = "select count(1) from [aspnet_Hr] where Id=@Id";的时候,比如:http://www.a.com/default.aspx?id=7就能正常显示,其它的也都能正常显示,提示记录存在,但当Id=10,即http://www.a.com/default.aspx?id=10,明明记录存在,但是提示记录不存在。
当把sql语句换成private const string SQL_SELECT_COUNT_ID = "select count(id) from [aspnet_Hr] where Id=@Id";后,一切都正常了!现在还没太清楚为什么?而在sql server 2005 里运行这两条语句,得到的结果是一样的!
select count(1) from [aspnet_Hr] where Id='10'
select count( Id) from [aspnet_Hr] where Id='10'
namespace ChinaFine.DAL
{
public class Hr:IHr
{
Database db = DatabaseFactory.CreateDatabase("WebDataBaseConnectionString");//声明db
private const string PARM_ID="@Id";
private const string SQL_SELECT_COUNT_ID = "select count(id) from [aspnet_Hr] where Id=@Id";
//下面这样写为什么当
private const string SQL_SELECT_COUNT_ID = "select count(id) from [aspnet_Hr] where Id=@Id";
#region IHr 成员
public bool Exists(int id)
{
DbCommand dbCmd = db.GetSqlStringCommand(SQL_SELECT_COUNT_ID);
db.AddInParameter(dbCmd, PARM_ID, DbType.Int32, id);
object obj = db.ExecuteScalar(dbCmd);
int cmdResult;
if (obj.Equals(null)||obj.Equals(System.DBNull.Value))
{
cmdResult=0;
}
else
{
cmdResult = int.Parse(obj.ToString());
}
if (cmdResult>0)
{
return true;
}
else
{
return false;
}
}
}
}
protected void Page_Load(object sender, EventArgs e)
{
ChinaFine.IDAL.IHr news = new ChinaFine.DAL.Hr();
if (news.Exists(Convert.ToInt32(Request.QueryString["id"])))
{
Response.Write("新闻存在");
}
else
{
Response.Write("新闻不存在");
}
}
昏倒,刚才又把项目重新生成一下,用两个都可以了!不知道是怎么回事?