3.6 Document Type Definitions (DTDs) vs. SchemaXSD

3.5 Entities in the DTD

An entity, by dictionary definition, is anything that exists. We used the term in Chapter 1 to mean all the parts that make up an XML document. We also used the term to mean predefined entities and showed Table 1.1, with these characters: & (ampersand), < (less than), > (greater than), ' (single quote or apostrophe), and " (double quote). Since the characters themselves are used to form markup or element tags, we need a way to include them in the content of the elements or the information of our document. Another usage for the term entities is to provide a standard set of shortcuts (or replacement text) to common words or phrases.

Table 3.1: Review of the predefined entities

Character

Entity

Name

&

&amp;

ampersand

<

&lt;

less than

>

&gt;

greater than

&apos;

apostrophe or single quote

"

&quot;

double quote

The predefined entities are needed to keep us from tripping over our own markup characters, and we do not need to declare them in our DTD. FileMaker Pro will automatically create the predefined entities for us. We could call them shortcuts so we do not have to add a complex set of instructions each time they are used. We can create our own shortcuts or entities by declaring general entities.

 General Entities <!ENTITY entityName replacementText> <!ENTITY mos "My Own String"> Parameter Entities <!ENTITY % entityName entityDefinition>



Filemaker Pro 6 Developer's Guide to XML(s)XSL
FileMaker Pro 6 Developers Guide to XML/XSL (Wordware Library for FileMaker)
ISBN: 155622043X
EAN: 2147483647
Year: 2003
Pages: 100
Authors: Beverly Voth

Similar book on Amazon

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net