当前位置: 首页 > 图文教程 > 网络编程 > ASP > javascript asp教程More About Recordsets

ASP
用asp执行DTC
利用ADODB.Stream使用浏览器下载服务器文件
应用数据库的唯一性约束并在asp中捕捉数据库的错误
用ASP编程控制在IIS建立Web站点
asp实现k线图(在线)
在ASP中用EasyMailObject组件处理Exchange邮件源代码(7)
在ASP中用EasyMailObject组件处理Exchange邮件源代码(6)
在ASP中用EasyMailObject组件处理Exchange邮件源代码(5)
在ASP中用EasyMailObject组件处理Exchange邮件源代码(4)
在ASP中用EasyMailObject组件处理Exchange邮件源代码(3)
在ASP中用EasyMailObject组件处理Exchange邮件源代码(2)
在ASP中用EasyMailObject组件处理Exchange邮件源代码(1)
用文本+ASP打造新闻发布系统。几点补充
用文本+ASP打造新闻发布系统(五)新闻修改
用文本+ASP打造新闻发布系统(四)新闻删除
用文本+ASP打造新闻发布系统(三)新闻列表显示
用文本+ASP打造新闻发布系统(二)新闻添加
ASP作的剪包锤游戏
ASP注册表项目修改
构建稳定的服务器端组件的七个步骤

ASP 中的 javascript asp教程More About Recordsets


出处:互联网   整理: 软晨网(RuanChen.com)   发布: 2009-09-13   浏览: 255 ::
收藏到网摘: n/a

Below we will attempt to access data from a database without knowing the column names. Clearly the best way to utilize data in your database is to keep track of your schema. Schema is the layout of data in your database. The concept is well beyond the scope of this web site, but it is worth mentioning. Most good resources on SQL will also be good resources on database management. Better database schema leads to better ASP code.

Get Started:

Below is the script for Lesson 18.

<%@LANGUAGE="JavaScript"%>
<!-- METADATA TYPE="typelib"
FILE="C:\Program Files\Common Files\System\ado\msado15.dll" -->
<HTML>
<BODY>
<%
var myConnect = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=";
myConnect += Server.MapPath("\\")
myConnect += "\\GlobalScripts\\htmlColor.mdb;";
var ConnectObj = Server.CreateObject("ADODB.Connection");
var RS = Server.CreateObject("ADODB.Recordset");
var sql="SELECT * FROM colorChart;";
ConnectObj.Open (myConnect);
RS.Open(sql,ConnectObj,adOpenForwardOnly,adLockReadOnly,adCmdText);
var recordCount = RS.Fields.Count;
var x = 0;
var getFieldNames = false;
Response.Write("<TABLE BORDER=\"1\" CELLSPACING=\"0\">\r");
while (!RS.EOF)	{	if (x >= recordCount)	{	x = 0	}	Response.Write("<TR>");	if (!getFieldNames)	{	while (x <= recordCount-1)	{	Response.Write("<TH>" + RS.Fields(x).Name + "</TH>");	x++;	}	getFieldNames = true;	x = 0;	Response.Write("</TR>\r<TR>")	}	while (x <= recordCount-1)	{	Response.Write("<TD>" + RS.Fields(x).Value + "</TD>");	x++;	}	Response.Write("</TR>\r");	RS.MoveNext();	}
Response.Write("</TABLE>\r");
RS.Close();
ConnectObj.Close();
RS = null;
ConnectObj = null;
%>
</BODY>
</HTML>

Click Here to run the script in a new window.

I don't think this needs much explaining. The RS.Fields.Count tells us how many columns wide the Recordset is. For each row, we loop through columns using either RS.Fields(x).Name for the colum name or RS.Fields(x).Value for the datum in said column.

Another Way:

A potentially more elegant way to accomplish this same goal is to use the ADO Method GetRows. It returns a multi-dimensional array containing the Recordset data. WAIT! Aren't JavaScript Arrays lexical (and flat)? Yes. We can emulate multi-dimensional arrays, but in reality they are flat. So it's a no-go on the GetRows... unless we do something really creative.

<%@LANGUAGE="JavaScript"%>
<!-- METADATA TYPE="typelib"
FILE="C:\Program Files\Common Files\System\ado\msado15.dll" -->
<HTML>
<BODY>
<%
var myConnect = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=";
myConnect += Server.MapPath("\\")
myConnect += "\\GlobalScripts\\htmlColor.mdb;";
var ConnectObj = Server.CreateObject("ADODB.Connection");
var RS = Server.CreateObject("ADODB.Recordset");
var sql="SELECT * FROM colorChart;";
ConnectObj.Open (myConnect);
RS.Open(sql,ConnectObj,adOpenForwardOnly,adLockReadOnly,adCmdText);
var myArray = RS.GetRows().toArray();
Response.Write("Let's see the results of myArray as JavaScript");
Response.Write(" sees them (which is flat).<BR>\r");
Response.Write(myArray + "<BR><BR>\r")
RS.MoveFirst();
var myVBArray = new VBArray(RS.GetRows())
Response.Write("We can use the <I>new VBArray</I> constructor and the ")
Response.Write("<I>getItem( )</I> method. For example: myVBArray.getItem(1,1) ")
Response.Write("returns " + myVBArray.getItem(1,1) + "<BR><BR>\r")
Response.Write("Now lets make something useful.<BR>\r")
Response.Write("<TABLE BORDER=1 CELLPADDING=0 CELLSPACING=0>")
Response.Write("\r<TR>")
for (var x=0; x<=myArray.length-1; x++)	{	Response.Write("<TD>" + myArray[x] + "</TD>")	if ((x+1)%RS.Fields.Count==0)	{	Response.Write("</TR>\r<TR>")	}	}
Response.Write("</TR>\r")
Response.Write("</TABLE>")
RS.Close();
RS = null;
ConnectObj.Close();
ConnectObj = null;
%>
</BODY>
</HTML>

Click Here to run the script in a new window.

Notice when we use getRows( ) we don't get the column names (but that would be really easy to fix). The problem with myArray is that it's not very useful in its raw state. So we use a modulo operator and thanks to a little thing called RS.Fields.Count we can tell how many times we write data to the table before staring a new table row.

If you like the new VBArray constructor you should know that you have the following methods: dimensions() getItem() lbound() toArray() and ubound().