javascript asp教程More About Recordsets

站长资源 2024/11/24 佚名

2 0 1

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().

javascript,asp教程More,About,Recordsets

广告合作：本站广告合作请联系QQ：858582 申请时备注：广告合作（否则不回）
免责声明：本站资源来自互联网收集,仅供用于学习和交流,请遵循相关法律法规,本站一切资源不代表本站立场,如有侵权、后门、不妥请联系本站删除！

评论“javascript asp教程More About Recordsets”

暂无评论...

《魔兽世界》大逃杀！60人新游玩模式《强袭风暴》3月21日上线

暴雪近日发布了《魔兽世界》10.2.6 更新内容，新游玩模式《强袭风暴》即将于3月21 日在亚服上线，届时玩家将前往阿拉希高地展开一场 60 人大逃杀对战。

艾泽拉斯的冒险者已经征服了艾泽拉斯的大地及遥远的彼岸。他们在对抗世界上最致命的敌人时展现出过人的手腕，并且成功阻止终结宇宙等级的威胁。当他们在为即将于《魔兽世界》资料片《地心之战》中来袭的萨拉塔斯势力做战斗准备时，他们还需要在熟悉的阿拉希高地面对一个全新的敌人──那就是彼此。在《巨龙崛起》10.2.6 更新的《强袭风暴》中，玩家将会进入一个全新的海盗主题大逃杀式限时活动，其中包含极高的风险和史诗级的奖励。
《强袭风暴》不是普通的战场，作为一个独立于主游戏之外的活动，玩家可以用大逃杀的风格来体验《魔兽世界》，不分职业、不分装备（除了你在赛局中捡到的），光是技巧和战略的强弱之分就能决定出谁才是能坚持到最后的赢家。本次活动将会开放单人和双人模式，玩家在加入海盗主题的预赛大厅区域前，可以从强袭风暴角色画面新增好友。游玩游戏将可以累计名望轨迹，《巨龙崛起》和《魔兽世界：巫妖王之怒经典版》的玩家都可以获得奖励。

更新日志

2024年11月24日

javascript asp教程More About Recordsets

javascript asp教程添加和修改

javascript asp教程Recordset记录

评论“javascript asp教程More About Recordsets”

《魔兽世界》大逃杀！60人新游玩模式《强袭风暴》3月21日上线

更新日志

友情链接