It will be found in this series of lectures or other information, although the XML standard itself is simple, but the standard related to XML has a wide variety of standards, there are more than 20 related standards developed by W3C, and important e-commerce standards developed by XML. more than ten. This aspect shows that XML is indeed a very practical structured language, and has been widely used; on the other hand, this is also difficult to learn to learn about these standards, in addition to the wide range of standards, standards usually also Take each other, especially the application standards, and their development is not only the XML standard itself, but also many other standards. What criteria is important for a particular application field? Which standards are based on other standards? What is the interrelationship between these standards? What is the XML standard system?
1 XML standard system
---- XML related standards can also be divided into three levels of meta-language standards, basic standards, and application standards, as shown in Figure 11-1.
--- Meta-Language: Described is a meta-language used to describe standards. In the XML standard system is the XML standard, the core of the entire system, and other XML-related standards are used to serve or serve them.
---- Foundation Standards: This level of standard is a standard for further practical use of XML, which specifies some public features, methods or rules that use XML to formulate standards. Such as: XML Schema describes a method of more stringent to define an XML document so that you can process an XML document more automated; XML NameSpace is used to ensure the consistency of the name in the XML DTD so that the names in different DTDs can be merged when needed. One document; etc. What are these basic standards? What is the interrelationship between them? The second half of this lecture will be discussed more detailed.
---- Application Standards: XML has begun to be widely accepted, a large number of application standards, especially for Internet applications, and XML is developed. Some people even think that the XML standard is the ASCII standard in the Internet era. In this Internet era, almost all industry areas are related to Internet. Once these industries have a relationship with the Internet, they must have their industry standards. These criteria tend to develop XML. Currently important application standards mainly include: standards for XML display: XHTML (Using XML to HTML redefine), SVG (related vector graphics), SMIL (related multimedia synchronization display), Mathml (related mathematical formula symbol) ); Standards for e-commerce domain: Micropayments (W3C Developed), BizTalk (Schema Library of Microsoft's Schema), EBXML (United Nations Un / Cefact Group and Oasis), PIP (by many IT A standardized organizational RosettaT application network standard.), CXML, XCBL, TPAML, etc.; and other areas.
2 XML basic standards and their relationships ---- From the XML standard system, it is very important to see XML base standards, and these standards are very important because these standards are the basis of XML application standards. On the basis of XML standards, they further clearly clearly specify some of the public features, methods and rules in XML. Application standards usually use the contents of these standards or the agreement to follow. In the use of XML, you also need to understand the contents of these standards when reading XML application standards. These standards have almost all involved in this series of lectures. In this lecture, they will be classified, and the interrelationship between these standards is mainly discussed. To readers can have a clearer understanding of these standards as a whole. ---- Figure 11-2 is a frame diagram for XML application standards. Figure 11-2
---- First, look at some of the standards of XML-related standards, those who have the meaning of the WEB application to determine the meaning of the architecture, and three standards on the left side of the broken line in Figure 11-2. These standards are not for XML standards or using XML standards, but they are the foundation of web applications, and they will be used almost anywhere in the web application. HTTP: Hypertext Transfer Protocol. URI / URL: Unified Resource Identifier / Uniform Resource Locator, is used to locate the resources on the Internet to uniquely identify any resource in a huge web information system. Unicode is a character encoding standard widely used in web applications, which will include almost all the texts in the world. The XML standard requires that the XML analyzer must support at least UTF-8/16 encoded Unicode characters. ---- The criteria shown in Figure 11-2 is second only to the XML standard itself, at the core position, and almost a set of standards used by all other XML-related standards. These standards are developed by the XML core working group (XML Core Working Group) to provide the most essential support for XML standards. XML Base, is used to define the basics of the URI of the XML document, similar to HTML BASE. XML Inclusions (XInclude), is used to specify the processing model and grammar rules for the included items in the document. Namespaces in XML, provides a simple way to limit the element name, attribute name conflict in the XML document by defining elements and attributes associated with the namespace from the URI reference identifier. Basic methods. Canonical describes a method of generating paradigm for the input XML document. ---- Treatment of four standard XML documents in Figure 11-2 provides effective methods and rules. Schema is a supplement to DTD, providing a more stringent method of describing the structure, attribute, data type, etc. of the XML document, so that the XML document can be more stringent automation. The DOM defines a set of interfaces that are unrelated to platforms and languages so that programs and scripts can dynamically access and modify the XML document content, structures, and styles. The purpose of XQuery is to extract data from the actual or virtual document in the Web, providing a flexible query mechanism. The key idea of XForms is to separate user interfaces and performances with data models and logically so that the same form can be widely applied to various situations such as handheld devices, desktop devices or voice-based browsers. ---- Everyone may be familiar with XSL, XLINK in Figure 11-2. Because this group of standards have prototypes in the HTML standard: display and link. And this is the most important and common content in HTML. At the same time, this group of standards fully inherited DSSSL and HYTIME related content in the SGML standard. In this group, XPath describes how to identify, select, and match each constituent element in the XML file, including elements, attributes, text content, and the like. XPointer and XLINK standards, inherit the contents of the location, links in Hytime standards, links the links in a separate element, and define "element elements" in the standard so as to have a variety of forms of the template or parent element. Wait. CSS is already very familiar, it starts to set up the display of HTML documents, as XML's appearance and development, it is also used as a style standard displayed by XML documents and will continue to use. However, the purpose of XML does not have its display, mainly in the description of the data content itself, where data conversion is one of its important content. To this end, the demand for developing XML conversion standards quickly, XSL is born. The development of XSL draws on the content and experience of DSSSL and CSS, such as the XSL standard to form a tree structure for XML documents, and use the element node matching, and the method of formatting the object is used for display formatting.
---- In Figure 11-2, there is also a portion of the reader's contact. RDF, PICS, P3P, XML-Signature. RDF (Resource Description Format) is a simple data model that uses XML syntax format processing metadata to describe a simple data model defined by interrelationships between images, documents, and them. Several States are generally using these criteria directly. But they are the basic standards for several Internet applications that use XML definitions. Online Series Publications Computer World Microcomputer World IT Manager World Household Computer World Digital Wealth
