Frequently Asked Questions about Getting Started with XML Part 2

[Introduction] View XML directly. The Microsoft XML implementation allows users to view XML through their Web browser using XSL or Cascading Style Sheets (CSS), just like an HTML document. High-performance, validating XML engine. Internet Explorer 4 0 Developer

View XML directly. The Microsoft XML implementation allows users to view XML through their Web browser using XSL or Cascading Style Sheets (CSS), just like an HTML document.

High-performance, validated XML engine. The XML engine familiar to Internet Explorer 4.0 developers has been greatly enhanced and comes with full support for W3C XML 1.0 and XML namespaces, allowing developers to uniformly qualify element names across the Web, thus avoiding conflicts between elements of the same name. conflict. Native XML support in Windows means that developers can use full XML processing capabilities to read and process data as they move it between applications and components.

Extensible Style Transformation Language (XSLT) support. Using the Microsoft XSLT processor, which is based on the latest W3C Working Draft, developers can apply style sheets to XML data and display the data in a dynamic and flexible way that is easy to customize. The query capabilities of the Microsoft XSLT processor also allow developers to programmatically find and extract information within XML data sets on the client or server.

XML Schema. Schema (English) Defines XML document rules, including element names and rich data types whose elements can be represented as combinations and whose attributes are available for each element. To enable multi-tier applications, Microsoft will release a technical preview of an XML schema based on the Reduced XML Data Schema (XDR) submitted to the W3C XML Working Group.

Server-side XML. Server-side XML processing allows the use of XML as a standard way to transfer data between multiple distributed application servers, even across operating system boundaries.

　XML Document Object Model (DOM). XML DOM is a standard object application programming interface that enables developers to programmatically control XML document content, structure, format, and more. The Microsoft XML implementation includes full support for the W3C XML DOM recommendations and can be accessed with scripting, the Visual Basic Development System, C++, and other programming languages.

　C++ XML data source object. XML DSO allows HTML elements to be bound directly to XML data islands. In addition, it has improved performance, has the powerful ability to bind to different XML nodes, and takes advantage of all the new data binding features in Internet Explorer 5 beta.
　What is the relationship between HTML, dynamic HTML and XML?

HTML can be used with CSS to format and represent hyperlinked pages. Dynamic HTML, through DOM, enables all elements in HTML to be accessed through language-independent scripts and other programming languages, thus greatly improving client-side interaction capabilities without requiring additional requirements for the server. . The page's object model allows any aspect of the content to be dynamically changed (including adding, deleting, and moving).

By adding XML to structured data, we provide developers with the technology to build the next generation of rich, flexible web applications. Using XML, they can provide structured data to the desktop and compute the data using the XML object model. Today's developers can display XML-based data through scripts in browsers such as Microsoft Internet Explorer 4.0 and Microsoft Internet Explorer 5 or in other applications. In addition, they can also apply formatting rules to the data without the need for complex scripts using XSLT stylesheets (which actually convert XML-based data to display). Both methods of displaying XML-based data make it possible to generate multiple views of complex data.

Why is XML so important?

XML will be the future of computing. As a technology, its influence will permeate every aspect of programming, from embedded systems to graphical interfaces to distributed systems and database management. It has actually become the standard for data communication between software industries and is quickly replacing EDI systems as the primary medium for business exchange in almost all industries around the world. It will likely become the language in which most documents are created and stored, whether on the Internet or not, and will likely become the basis for Internet application servers, with some believing it will replace many of the small package products currently produced.

　What XML products does Microsoft offer?

Microsoft is working to develop XML resources for many areas:

Data access. The latest incarnation of ActiveX® Data Objects (ADO) has supported the generation and consumption of XML for nearly a year, and Microsoft SQL Server 2000 provides a number of interfaces for converting SQL-based information to and from XML.

Browser support. Microsoft was the first company to produce a commercial browser (Internet Explorer 5) that could read XML files, either in their raw structured form or through XSL or CSS stylesheets.

　BizTalk Server 2000. Microsoft® BizTalk(TM) Server 2000 provides a way to communicate between a number of different formats, including XML, to help drive business-to-business applications. BizTalk Server also includes a number of schema generation and mapping tools that greatly simplify the development of XML structures for business or commercial needs.
Does XML need to be compressed for transmission on the Web?

Generally speaking, the need to compress XML is application-specific and is largely a function of the amount of data moved between the server and client. The iterative nature of the tags used to describe data structures makes XML very good at compressing data. It's worth noting that compression is standard for both HTTP 1.1 servers and clients, and XML automatically benefits from it.

How secure is XML as a data format? Are there any plans to increase XML security?

XML is as safe as HTML. Just as Secure HTTP (HTTPS) can be used to protect HTML by adding cryptographic techniques to HTTP, it can also be used to protect XML. XML is a text-based format for representing structured data. This maximizes data simplicity and interoperability. There are many steps you can take to add security and validation capabilities to your XML format. First, XML can be encrypted on the server before being transmitted to the client, and then decrypted on the client. Digital signatures applied to the data itself can also verify XML.

　Confirmation

　What is a DTD and its uses?

　A Document Type Definition (DTD) defines the correct syntax for a class of XML documents. That is, it lists a number of element names, what elements can be displayed with other elements, what attributes can be used for each element type, and so on. DTDs use different syntax forms that XML documents use.

Must web developers include DTDs when using XML to describe data?

No. XML can be used to describe data with or without a DTD. The term "valid" XML refers to XML data that references a DTD, while "well-formed" XML is XML that does not use a DTD. Additionally, "well-formed" XML is one of the fundamental differences between XML and Standard Unified Markup Language (SGML). Obviously, in both cases, the XML itself must adhere to the language's standards (for example, all tags must be closed, and tags cannot overlap).

　What is XML Schema? How do they differ from DTDs?

Although XML 1.0 provides a mechanism for defining the content model of an XML document - a DTD - it is clear that a more comprehensive and efficient way of defining a content model is needed. An XML schema is a definition of a special XML structure (both in terms of its organization and data types). XML Schema uses the XML Schema language to specify how each type of element is defined in the schema and the data type associated with the element. Compared with DTD, the most distinctive feature of the schema is that the schema itself is an XML document. This means that tools that read the XML it describes can also read it.

Microsoft's XML service currently supports the XML Data Schema, which represents a snapshot of "W3C Schema" activity when Internet Explorer 5 shipped in March 1999. XML data schema allows developers to add data types to their XML documents, as well as define open content models. This extension of DTD functionality is critical to XML programming.

　But W3C is preparing "XML Schema Definition (XSD)", which will become the "XML Schema Standard". Microsoft plans to make support for XML Schema Definition (XSD) part of its core XML services as soon as this specification becomes a recommendation.

　What are namespaces and why are they important?

Namespaces are another advanced feature of XML and are outlined in W3C notes as part of the XML 1.0 specification. They allow developers to qualify element names and relationships. Namespaces make element names uniquely identifiable, thus avoiding name conflicts between elements with the same name but defined in different dictionaries. They allow mixing tags from different namespaces, which is important for data from multiple sources.

Namespaces help clearly define this difference.

　XSLT and XPATH

　What is XSLT?

　XSLT (English), or Extensible Stylesheet Language for Transformations, is a W3C recommendation approved on November 6, 1999. In both a markup and programming sense, this language provides mechanisms for transforming XML structures into other XML structures, HTML, or any number of other text formats (such as SQL). Although it can be used to create the display output of a Web page, the real power of XSLT is the ability to change underlying structures rather than simply changing the media representation of those structures, as in Cascading Style Sheets (CSS).

　What is the difference between XSL, XQL, XSL Schema and XSLT?

　XSLT originated from the limitations of CSS in changing the structure of XML documents. The reason for creating XML at that time was more to replace HTML than to provide a universal data description language. Extensible Stylesheet Language (XSL) thus emerged as the result of a new way of constructing formatted XML.

However, members of the W3C Style Working Group and early adopters of XML soon discovered that a language that could transform XML from one format to another could greatly simplify the large amounts of code that was generated. Microsoft submitted a proposal to the W3C, originally named XML Query Language (or XQL), which was subsequently adopted by the W3C as the XSL Schema Language. Most features of the language were eventually incorporated into the XSLT specification.

The final standard incorporates modified XSLT parameters for different initial conditions, named templates for creating code function blocks, and a number of enhancements for numeric and string processing. XSLT also facilitates the addition of built-in functionality into the language, providing products that Microsoft can use to add many extremely useful features to its own implementations, including access to COM objects and scripts.

　What is XPath?

　XPath (English) is a query language defined for XML that provides a simple syntax for selecting a subset of nodes in a document. With XPath, you can retrieve a collection of elements by specifying a directory-like path (that is, a name) and conditions within the path. XPath is central to both XSLT and XML DOM, and is tied to the XPointer specification, which allows the selection of document fragments based on a combination of Uniform Resource Locators [URL] and XPath expressions.

Why is XSLT important for XML?

　XSLT is a language that transforms one XML document into another. This means that it provides a mechanism for single-source XML data, the ability to create rich views in Web pages that are dynamically changed by users, and the ability to filter data for targeted communications. XSLT is powerful enough for coding business rules. It can generate graphics from data (not just web pages). It can even handle communication with other servers—especially working with script modules that can be integrated into XSLT—as well as generating appropriate messages within XSLT itself. While it's unlikely to replace most interactions on desktop systems (for both performance and ease-of-use reasons), there's a good chance that in the coming years XSLT will eventually become the primary "programming" for communicating between systems. language.

　What is the difference between XSLT and CSS? Aren't they style sheets?

Cascading Style Sheets (CSS) are tasked with specifying a set of display properties for HTML elements. CSS determines the visual appearance of the page but does not change the structure of the source document.

On the other hand, XSLT, also known as a template-based language, allows a pattern to be mapped into a source document whose output is written in XML, HTML, or plain text. Using XSLT, you can transform the structure of an XML document into different XML documents. For example, you can change the order of an XML document, add or remove elements, perform conditional testing, or iterate over a collection of elements.

　XSLT and CSS are not compatible standards. A useful technique for creating Web pages in XML is to use XSLT to transform the XML into structures such as lists or tables, and then apply CSS to the results to control the display of these structures in the appropriate media. You can even create CSS from XSLT.

　Standards

　How is Microsoft compatible with the XML standard?

Since the inception of the XML language, Microsoft has been at the forefront of XML, and it is worth noting that most of the XML recommendations and working drafts produced by the W3C in the past few years include contributions from Input and participation from at least one (and in some cases possibly several) Microsoft employees. Microsoft has been entrusted with the task of ensuring that XML is developed to benefit all users, along with the W3C standards body, and has made important contributions to the development of many different areas, including the XML specification, DOM, XSLT, and Schema Definition Language . Microsoft is committed to maintaining compliance with the latest specifications and standards.

　What is the relationship between XML and the World Wide Web Consortium (W3C)?

The W3C has an active XML working group. Microsoft has been a co-sponsor of the organization since June 1996, and many industry players have joined since then, including Netscape Communications Corp., IBM and Oracle. For more information about the XML standards process, visit the W3C Web site (in English).

　What is the status relationship between XML and W3C?

XML 1.0 was officially approved in December 1998 and is still a stable standard. For more information about the current XML specification and the submission and review process within the W3C, see the W3C Web site (in English).

　What is the status of DOM in W3C?

　The W3C document status of DOM Level 1 is "Recommended". This means that the W3C is currently proposing it as a standard on the World Wide Web. For more information about DOM and the submission and review process within the W3C, see the DOM Specification (in English).

　Tool support

Does SQL Server and ADO support XML?

Microsoft ActiveX Data Objects (ADO) technology provides many methods to convert database record sets (data record collections) into XML format, as well as obtain XML from a given structure and convert it back to an ADO supported database (including SQL Server and Oracle database). In addition, through the XML data source object in MSXML2 and MSXML3, arbitrary XML can be loaded directly into ADO to generate a recordset.

SQL Server 2000 also allows XML to be set and retrieved directly from a URL, much like calling a Web page. This is a powerful mechanism for working with data because it basically means that SQL Server data can be integrated directly into XML filters and Web pages, basically anywhere there is an XML document. In addition, you can set up custom templates to control how XML is generated from SQL Server data, making the database a powerful tool for generating XHTML pages.

Finally, applications such as BizTalk Server also allow mapping between any number of different data sources (from XML documents to databases to Excel and Word documents), creating complex data pipelines for Web architectures, and Construct effective schema based on XML database requirements.

Are there any Microsoft tools that can help me quickly adopt XML?

Microsoft BizTalk Server 2000 is an XML-based server for data exchange that provides the basic structure and tools to enable an e-commerce business community. The foundation of BizTalk Server is a basic structure of rules-based routing, transformation, and tracking of business documents. This basic structure allows companies to integrate, manage, and automate business processes by exchanging business documents, such as purchase orders and invoices, between applications within or between organizational boundaries. For more information, see Microsoft BizTalk Server 2000 (English).

　What is SOAP?

　SOAP is Simple Object Access Protocol and a tool for creating large-scale distributed, complex computing environments that can run on the Internet using the existing Internet infrastructure. SOAP enables applications to communicate directly with each other over the Internet in many ways. For more information about SOAP, see the SOAP specification (in English).

　How does XML fit into Microsoft Windows? Distributed InterNet applications (Windows DNA) strategy to construct three-tier, Web-enabled applications?

XML is quickly becoming the tool for delivering structured data from the middle tier to the desktop. XML-based data can be integrated with a variety of back-end (database) sources through middle-tier proxies. Schemas (see the "XML Data" section) can improve this process and allow developers to describe and exchange data more precisely.

　Problems and Solutions

Why is my document object still empty after calling the Load() method?

By default operations are loaded asynchronously. This means that if an http URL address is provided, the load() method will return directly and the document object will still be empty because the data has not been returned from the server. To correct this problem, add the following line to your code: The message queue can continue to load.

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