数据库动态数据的处理+Repeater前台动态列的绑定
问题描述：
如图所示：数据库中有两张表，一张表可以根据课程id选出所有该课程的学生信息，另外一张表可以根据课程id选出该课程所有学生各次考试的成绩。由于考试次数是由老师自己动态设定的，事先并不清楚考试次数到底是多少。（.NET+Oracle网站实现）
1、首先，解决此类问题可以通过Repeater嵌套实现，对于数据量不大的时候可以这么用，但是一旦数据量稍大处理时间会变得很长，效率太差。
2、写个存储过程将所有数据整理成一张表，然后一次绑定到前台控件。
下面是该案例的存储过程：
create or replace procedure sp_get_all_cj(p_xkkh in varchar2, p_cursor out sys_refcursor)
is
sqlstr varchar2(32767);
ct integer;
begin
sqlstr:='with cjj as ( select a.xh, b.xm, ';
for v_cur in (select distinct id, ksmc,ksbh from gcgl.ksxxb where xkkh = p_xkkh
order by ksbh )
loop
sqlStr := sqlstr || 'sum(case ksid when '''|| v_cur.id ||''' then xscj else null end ) as c'|| v_cur.ksbh ||',';
end loop;
sqlstr := substr(sqlstr,0,length(sqlstr)-1) ||' from gcgl.xsksb a join gcgl.v_xsb b on a.xh = b.xh ' ||
'where exists ( select * from gcgl.ksxxb b where a.ksid = b.id and b.xkkh = '''
|| p_xkkh || ''') group by a.xh, b.xm ) ' ;
select count(*) into ct from gcgl.xszzcjb where xkkh = p_xkkh;
if (ct >0) then--说明已经提交了
sqlstr := sqlstr || ' select rank() over( order by b.xh) rowno, b.*, a.zpcj '
|| ' from gcgl.xszzcjb a left join cjj b on a.xh = b.xh '
|| ' where a.xkkh = '''
|| p_xkkh
|| ''' order by b.xh';
else
sqlstr := sqlstr || ' select rank() over( order by b.xh) rowno, b.*, 0 zpcj '
|| ' from cjj b order by b.xh';
end if;
open p_cursor for sqlstr;
end;
然后是以下C#语句，读出这张表，放到dataTable中
using (OleDbConnection con = new OleDbConnection(ConfigurationManager.ConnectionStrings["JSCJLR"].ToString()))//连接字串
{
OleDbCommand myCMD = new OleDbCommand
("{call gcgl.sp_get_all_cj(?, {resultset 0, p_cursor})}", con);
myCMD.Parameters.Add("p_xkkh", OleDbType.VarChar, 100).Value = xkkh;
OleDbDataAdapter oda = new OleDbDataAdapter(myCMD);
DataSet ds = new DataSet();
oda.Fill(ds);
dt = ds.Tables[0];
}
读出的表结构大致是
xh,c1,c2,c3,c4...等，其中c1,,c2...是动态列，表示的是第几次考试
接下来的问题就是，有一个动态列的表，如何将该表绑定到前台控件中。
前台：
<table id="table" cellspacing="0" summary="The technical specifications of the Apple PowerMac G5 series">
<caption> </caption>
<asp:Repeater runat="server" ID="Repeater" OnItemDataBound=" rptClass1_ItemDataBound">
<headerTemplate>
<asp:Literal ID="lit_head" runat="server"></asp:Literal>
</headertemplate>
<itemtemplate>
<asp:Literal ID="lit_item" runat="server"></asp:Literal>
</itemtemplate>
</asp:Repeater>
</table>
后台：
protected void rptClass1_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
StringBuilder sb = new StringBuilder();
if (e.Item.ItemType == ListItemType.Header)
{
sb.Append("<tr>");
for (int i = 0; i < dt.Columns.Count; i++)
{
DataColumn col = dt.Columns[i];
string name = col.ColumnName;
switch(col.ColumnName){
case "ROWNO": name = "序号"; break;
case "XH": name = "学号"; break;
case "XM": name = "姓名"; break;
case "ZPCJ": name = "总评成绩"; break;
default:
string s = col.ColumnName;
name = s.Substring(1, s.Length - 1);
break;
}
sb.AppendFormat("<th>{0}</th>",name );
}
//foreach (DataColumn col in dt.Columns)
//{
// sb.AppendFormat("<th>{0}</th>", col.ColumnName);
//}
sb.Append("<th>平均分</th><th>最高分</th><th>最低分</th>");
sb.Append("</tr>");
Literal literal = (Literal)e.Item.FindControl("lit_head");
literal.Text = sb.ToString();
}
else if (e.Item.ItemType == ListItemType.Item||e.Item.ItemType == ListItemType.AlternatingItem)
{
int index=e.Item.ItemIndex;
sb.Append("<tr rel=''>");
sb.AppendFormat("<td>{0}</td>", index + 1);
for (int j = 1; j < 3; j++)
{
sb.AppendFormat("<td>{0}</td>", dt.Rows[index][j]);
}
for (int j = 3; j < dt.Columns.Count - 1; j++)
{
sb.AppendFormat("<td rel='cj'>{0}</td>", dt.Rows[index][j]);
}
for (int j = dt.Columns.Count - 1; j < dt.Columns.Count; j++)
{
sb.AppendFormat("<td>{0}</td>", dt.Rows[index][j]);
}
sb.Append("<td rel=\"pjf\"></td><td rel=\"zgf\"></td><td rel=\"zdf\"></td>");
sb.Append("</tr>");
Literal liter = (Literal)e.Item.FindControl("lit_item");
liter.Text = sb.ToString();
}
}
自此就实现了数据的动态操作了。