Why XML?

Why XML?

There already exists a standard for defining markup languages like HTML. 
What's wrong with these markup languages? Why do we need XML? The main 
point of XML is that, by defining your own markup language, you can encode 
the information of your documents much more precisely than is possible 
with HTML. This means that programs processing these documents can 
"understand" them much better and easier, and therefore process the 
information in ways that would be impossible with HTML (or any other 
free-form text formats). Imagine that you marked up inventory items 
(for, say, product ID and quantity etc) according to a schema tailored 
for inventory where you entered the stock level of each inventory and 
the supplier track records. You could then easily make a program that, 
given a list of the inventory items, would go through the entire list 
and make a list of orders in order to fulfill a given new order. 
Given the urgency of the order and pricing etc., the program could 
sort the suggestions by the best suppliers and summarize the costing, 
or by how long they'd take to ship, etc. The possibilites are almost 
infinite, because the information is encoded in a way that the computer 
can "understand". 

With the power of XML, information can be encoded in a more meaningful way. 
In addition, with an optional DTD or XML Schema which gives a standard 
format for information related to a specific subject, it can be used to 
simplify the exchange of information between different sources. Many 
kinds of applications have or will have standard DTDs or XML Schemas. 
In fact, more than 200 of such standards for different applications 
(e.g., financial news, oceanology, chemistry, mathematics, banking) 
have been defined (readers can find the details of these standards 
from www.oasis-open.org). This means that systems of these industries 
can use these common DTDs or XML Schemas to exchange information with 
each other, regardless of their internal format. 

Technically speaking, because of the increasing popularity of XML, 
we will see a higher and higher degree of tightly coupling between 
XML and Java, XML and .NET, XML and other Web/mobile standards. 
Therefore, we foresee the role of XML is becoming increasingly 
important everyday. 

To learn more about XML and its applications for World-Wide Web, 
please enroll the seminar held by the Department of Computer Science, 
Hong Kong Baptist University as follows:

Speaker: 	Dr. Raymond Wong 
(Senior Lecturer, The University of New South Wales, Australia) 
Date: 		June 16-25, Wednesday and Friday, 6:30 p.m.-8:30 p.m.
Course Fee: 	HK$950
Homepage: 	http://www.comp.hkbu.edu.hk/~training








為什麼用XML?

目前已經存在一個用來定義標記的語言標準，如HTML。這些標記語言有什麼問題嗎？
為什麼我們需要XML? XML的主要作用在於通過定義你自己的標記語言，你可以給你的
文檔資訊編碼，這些編碼會比用HTML編碼更為精確。這就意味著處理這些文檔的程式
能夠更好，更容易地"理解"他們，因此，處理這些資訊的方法可能是HTML（或其他任何
文本格式）所不能夠進行的。設想下面的情況，為記錄你的詳細存貨清單，你要根據
一個為目錄而定制的schema來標記存貨目錄條目（比如productID和quantity等等），
供應商將追蹤這些記錄來供貨。你可以很容易地做一個程式來實現，給定目錄條目列表，
遍曆全部列表，制定新的訂單清單，從而完成一個給定的新訂單。如果考慮訂單和價格
的緊急情況等等，這個程式還可以對供應商給出排序的建議，並且總計費用，或者
對多長時間到貨等等排序。各種可能性幾乎是無限多的，因為資訊是通過電腦可以
"理解"的方式進行編碼的。

通過XML，資訊可以以更有意義的方式進行編碼。另外，通過選擇DTD或則
XML Schema（XML Schema是為相關一個特定主體的資訊提供一種標準格式），
它能簡化在不同資訊源之間的資訊交換。許多實際應用已經或者即將擁有標準的DTDs 
或者XML Schemas。事實上， 超過200個這樣的不同應用領域（舉例來說，財經新聞，
海洋資源研究，化學，數學，銀行業）的標準已經被定義（讀者可以從這裏
www.oasis-open.org查找這些標準的詳細資訊）。這就意味著這些工業系統可以
使用公共的DTDs或者XML Schemas來彼此交換資訊，而不用考慮其系統內部的格式。

從技術的角度來說，因為XML變得更加流行，我們將會看到XML和Java，XML和.NET，
XML和其他的Web/mobile標準緊密結合的程度越來越高。因此，我們可以預見XML
的作用已經變得越來越重要。

想知道更多關於XML和它在互聯網上的應用，請報名參加浸會大學計算機科學系
專題討論會，詳情如下:

講者: 黃國基博士 (澳洲新南威爾斯州大學高級講師)
日期: 六月十六至二十五日，逢星期三及星期五，晚上六時三十分至八時三十分
費用: HK$ 950
網址: http://www.comp.hkbu.edu.hk/~training