XML Schema learning (1)

Source: Internet
Author: User
Tags xmlns
Recently, I have worked hard to read the WMFC-defined interface 1 standard document. XML Schema is used for the definition of XML format. XML Schema plays a major role in many aspects, there is a tendency to replace DTD, so I wrote some study notes here. Please correct me if you have any omissions!

Other aspects of XML Schema may not be here, so they will go directly to the topic, concerning the basic syntax of XML Schema.

XSDL (XML Schema Definition Language) is composed of elements, attributes, namespaces, and other nodes of the XML document type.

I. Elements in XSD

The XSD document must include at least the schema root element, the XML schema namespace definition, and the element definition.

1. schema root element

<Xsd: schema xmlns: xsd = "http://www.w3.org/2001/xmlschema">
</Xsd: schema>

Only one schema root element must be defined in XSD. The root element includes schema constraints, XML schema namespaces, definitions of other namespaces, version information, language information, and other attributes.

2. Elements

<Xsd: element name = "user" type = "xsd: string"/>

Elements in XSD are declared using element identifiers. Here, the name attribute is the name of the element, and the type attribute is the type of the element value. Here it can be the built-in data type in XML Schema or other types.

<Xsd: schema xmlns: xsd = "http://www.w3.org/2001/xmlschema">
<Xsd: element name = "user" type = "xsd: string"/>
</Xsd: schema>
The valid XML documents corresponding to the above documents are as follows:
<? Xml version = "1.0"?>
<User> string </user>

The element definition has two attributes: minOccurs and maxOccurs. MinOccurs defines the minimum number of times this element appears in the parent element (1 by default, and the value is an integer greater than or equal to 0 ), maxOccurs defines the maximum number of times this element appears in the parent element (1 by default, and an integer greater than or equal to 0 ). In maxOccurs, you can set the value to unbounded, indicating that there is no limit on the maximum number of times an element appears.

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.