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

ASP
ASP中用Join和Array,可以加快字符连接速度。
采用ODBC接口访问MySQL指南
最大限度优化你的Asp性能
实现让每句话的头一个字母都大写
如何尽快释放掉Connection对象建立的连接?
把数据插入到数据库的两种方法
Connection对象的应用
查看ASP Session 变量的小工具
用XMLHTTP组件正确解析图片地址并将其保存
利用XMLHTTP 从其他页面获取数据
Request与Request.Form的速度测试
用SOAP和ASP进行服务器端更新
ASP开发网页时需要牢记的注意事项列表
面向对象的ASP技术:思考与实践
提供一种“间接防止另存为”的方法
格式化数字函数FormatNumber
怎么样写一段高效,安全的sql查询代码
关于Adodb.Stream的使用说明
不用EOF以加快记录循环
防止重复提交的巧妙方法

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: 228 ::
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().