随机得到Access数据库记录-.NET教程,数据库应用

由于access数据库记录集缓存的原因，从代码里得到access数据库随机记录是得不到，需要用随机sql语句的办法来消除缓存。

下面就是例子：

查看例子http://dotnet.aspx.cc/exam/getrandom.aspx

<%@ page language=”c#” debug=”true” %>
<%@ import namespace=”system.data” %>
<%@ import namespace=”system.data.oledb” %>
<title>随机得到access数据库记录</title>
<script runat=”server”>
void page_load(object src,eventargs e)
{
if(!ispostback)
 {
 string myconnstring = “provider=microsoft.jet.oledb.4.0;data source=”
        + server.mappath(“aspxweb.mdb.ascx”);
 random r = new random();
 int intrandomnumber = r.next(1,1000);

 string sql = “select top 10 id as 序号,title as 标题 from document order by rnd(“
      + (-1 * intrandomnumber).tostring() + “*id)”;
 oledbconnection myconnection = new oledbconnection(myconnstring);
 myconnection.open();
 oledbcommand cmd = new oledbcommand(sql,myconnection);
 oledbdatareader dr = cmd.executereader();
 
 datagrid1.datasource = dr;
 datagrid1.databind();
 cmd.dispose();
 myconnection.close();
 myconnection.dispose();
 myconnection = null;
 }
}

</script>
<form runat=server>
<asp:datagrid id=”datagrid1″ horizontalalign=”center”
 width=”600px” runat=”server” font-size=”9pt”>
 <alternatingitemstyle backcolor=”#eeeeee”></alternatingitemstyle>
 <headerstyle backcolor=”#aaaadd” font-bold=”true” horizontalalign=”center” />
</asp:datagrid>
</form>