While this section is devoted to ASP database utilization, it very important to remember that this web site is not intended to be a thorough ASP resource. Remember, the focus of this site is strictly limited to how to use JavaScript as your primary scripting language for ASP.

You'll see how to construct connection strings in JavaScript, use JavaScript loops to manipulate recordsets, convert the JavaScript Date Object into a format that databases can accept, and to some extent you'll see how to make SQL statements in JavaScript.

You can find a lot of good resources on database utilization. Those resources, coupled with the next four lessons, will be everything you need to write ASP JavaScript database applications.

The Connection Object:

The connection object is the link between the database and your ASP script. Remember, it's a created or instanciated object, so we can have two or more instances of Connection on one page. Connection has eight (8) methods, eleven (11) properties, nine (9) events, and finally it has two (2) properties. We will discuss three of the methods, one of the properties, and then we will forego the rest.

There are four common connections. 1) MDL 2) DSN 3) ODBC 4) OLE-DB. MDL stands for Microsoft Data Link. Don't use it. Also, please don't use a DSN; it's slow and outdated and nobody recommends it. ODBC is better, but it's not the best. The recommended connection type is OLE-DB. That's the type of connection you'll see demonstrated below.

Get Started:

Below is the script for Lesson 16. Don't try to understand it yet. We will slowly pick this thing apart down below.

<%@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 ID, colorName, hexValue FROM colorChart;";

ConnectObj.Open (myConnect);
RS.Open(sql,ConnectObj,adOpenForwardOnly,adLockReadOnly,adCmdText);

Response.Write("<TABLE BORDER=\"1\" CELLSPACING=\"0\">\r");
Response.Write("<TR><TH>ID</TH><TH>colorName</TH>");
Response.Write("<TH>hexValue</TH></TR>\r");
while (!RS.EOF)
	{
	Response.Write("<TR><TD>" +RS("ID")+ "</TD><TD BGCOLOR=\"#");
	Response.Write( RS("hexValue")+ "\">" + RS("colorName") );
	Response.Write("</TD><TD>" +RS("hexValue")+ "</TD></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.

Connection String:

This is by no means the most sophisticated database application ever built, but it will demonstrate everything we need to do. Let's start by looking at the connection string reprinted below.

var myConnect = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source="; 
myConnect += Server.MapPath("\\ASP") 
myConnect += "\\GlobalScripts\\htmlColor.mdb;";

That does look different than a VBScript connection string. As a matter of fact, let's compare.

Dim myVBconnect;
myVBconnect = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=";
myVBconnect += Server.MapPath("\ASP") 
myVBconnect += "\GlobalScripts\htmlColor.mdb;";

We already talked about escape characters in lesson 02. We won't revisit them here. Down below you'll see that we use myConnect as an argument in the Open() method.

Managing the Connection:

I want you to pay attention to the next four lines of code that I reprinted below. First we instanciate a Connection Object.

var ConnectObj = Server.CreateObject("ADODB.Connection");

Then we open the Connection.

ConnectObj.Open (myConnect);

Then the Connection Object becomes the second argument in the Recordset Open() method.

RS.Open(sql,ConnectObj,adOpenForwardOnly,adLockReadOnly,adCmdText);

And lastly, when we are finished with the Connection, we close it.

ConnectObj.Close();

Next Up:

There is a lot of code left unexplained in this example. We'll repeat the same script in lesson 17 and go over most of what we left out the first time through.

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!

《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。