Datasheet

❑ Attributes are not expansion friendly. It is more difficult to change metadata than it is to

change data. It should be. If you have to change metadata then there might be data structural

design issues anyway. In a purely database environment (not using XML), changing the

database model is the equivalent of changing metadata. In commercial environments metadata

is usually not altered because it is too difficult and too expensive. All application code depends

on database structure not being changed. Changing database metadata requires application

changes as well. That’s why it can get expensive. From a perspective of XML and XML in

databases, you do not want to change attributes because attributes represent metadata, and

that is a database modeling design issue — not a programming issue. Changing the data is

much, much easier.

Try It Out Using XML Syntax

The following data represents three regions, containing six countries, as in the previous Try It Out sec-

tions in this chapter. In this example, currencies are now added:

Africa Zambia Kwacha

Africa Zimbabwe Zimbabwe Dollars

Asia Burma

Australasia Australia Dollars

Caribbean Bahamas Dollars

Caribbean Barbados Dollars

In this example, you use what you have learned about the difference between XML document elements

and attributes.

The following script is the XML document created in the first Try It Out section in this chapter:

<?xml version=”1.0”?>

<region>Africa</region>

<country>Zambia</country>

<country>Zimbabwe</country>

<country>Burma</country>

<region>Australasia</region>

<country>Australia</country>

<region>Caribbean</region>

<country>Bahamas</country>

<country>Barbados</country>

</regions>

You will use the preceding XML document and add the currencies for each country. Do not create any

new elements in this XML document.

Change the XML document as follows:

1. Open the XML document. You can copy the existing XML text into a new text file if you want.

Chapter 1

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