Basic XML knowledge learning

Basic XML knowledge:

XML features: XML has nothing to do with the operating system and programming language development platform.

Implement data interaction between different systems

XML: Extensible Markup Language

HTML:

XML structure:

  <?xml version ="1.0" encoding ="UTF-8" ?>

-- XML file declaration Encoding

If you do not write, the default is UTF-8.

<Root element>
<Child element 1 Property = "value">
<Element> value </element>
<Element> value </element>
<Element> value </element>
</Child element 1>
<Child element 2 Property = "value">
<Element> value </element>
<Element> value </element>
<Element> value </element>
</Child element 2>
<Child element 3 property = "value">
<Element> value </element>
<Element> value </element>
<Element> value </element>
</Child element 3>
</Root element>

1. There can be only one root element and multiple child elements

2. XML tags are case sensitive.

3. xml must be correctly nested

Use of the CDATA section:

<? XML version = "1.0" encoding = "UTF-8"?> <Books> <author> Wang Shan </author> <title> XML advanced programming </title> <description> <! [CDATA [describes the writing of null elements, for example, <title> </title> <title/>]> </description> </books>

Annotations in XML: <! -->

For example:
<Contestant>
<Contestant>
<Contestant Name> Wang xianming </contestant Name>
<Expected score> 75 </expected score>
<Actual score> 80 </actual score>
</Contestant>
<Contestant>
<Contestant Name> Zhang Fei </contestant Name>
<Expected score> 90 </expected score>
<Actual score> 80 </actual score>
</Contestant>
<Contestant>

Namespace: <xmlns: tea = "http://www.tea.org">

DTD Technology

Role of a DTD file: used to verify and constrain the format of an XML file

There are three types of DTD documents:

Internal DTD document <! Doctype root element [definition content]>

External DTD document <! Doctype root element system "DTD file path">

Internal and external DTD document <! Doctype root element system "DTD file path" [definition content]>

Example:
 

 <? xml version="1.0"?> <!DOCTYPE poem[    <!ELEMENT peom(author,title,content)>    <!ELEMENT author(#PCDATA)>    <!ELEMENT title(#PCDATA)>    <!ELEMENT content(#PCDATA)> ]>

XML file section

Syntax of elements in DTD:

<! Element name content>

Syntax of attributes in DTD:

<! ATTLIST element name
Attribute name attribute type attribute Characteristics
............
>

The property types include CDATA, ID, idref/idefs, and enumerated.

Attribute features: # required, # implied, # fixed value, and default value

Entity:

Syntax for defining objects: <! Entity entity name "entity value">

Example: <! Entuty writer "Donald Duck">
Example: <! Entuty copyright "Copyright w3schools">



Schema basics:

Root element: Schema

Elements used to define elements and attributes:
 
Element, attribute

Group, attributegroup

Used to define a simple type: simpletype

Used to define a complex type: complextype

Type constraints: choice, list, sequence, Restriction

This article is from The Rock blog, please be sure to keep this source http://chi474879271.blog.51cto.com/9253467/1551703

Basic XML knowledge learning