Frequently asked questions in XML (ii)

What level of support does Internet Explorer 5.0 provide for XML?

Internet Explorer 5 provides the following XML support:

View the XML directly. Microsoft XML implementations allow users to view XML through their Web browsers using XSL or cascading style sheets (CSS), just as they would view HTML documents.

High performance, validating XML engine. The XML engine familiar to Internet Explorer 4.0 developers has been greatly enhanced and fully supports the Universal XML 1.0 and XML namespaces, so that developers can uniformly qualify element names on the WEB, thereby avoiding conflicts between elements of the same name. Native XML support in Windows means that when developers move data between applications and components, they can use the full XML processing functionality to read and process data.

Extensible Style Conversion Language (XSLT) support. With the Microsoft XSLT processor based on the latest Working Draft, developers can apply style sheets to XML data and display data in dynamic and flexible ways that are easy to customize. The Microsoft XSLT processor's query functionality also allows developers to use programs to find and extract information within an XML dataset, either on the client or on the server.

XML schemas. Schemas (English) define XML document rules, including element names and rich data types, whose elements can be represented as combinations, and the attributes of each element are available. To enable multi-tier applications, Microsoft publishes a technical preview of the XML schema based on the reduced XML data schema (XDR) submitted to the Consortium's XML workgroup.

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

The XML Document Object Model (DOM). The XML DOM is a standard object application programming interface that enables developers to control the content, structure, format, and so on of XML documents.

Microsoft XML implementations include full support for the recommendations of the Consortium's XML DOM, and can be accessed using scripts, Visual Basic development Systems, C + +, and other programming languages.

C + + XML data source object. XML DSO allows HTML elements to be directly bound to an XML data island. In addition, it improves performance, has the power to bind to different XML nodes, and leverages all the new data-binding capabilities of 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 the DOM, enables all elements in HTML to be accessed through language-independent scripts and other programming languages, thereby greatly improving client-side interaction and eliminating the need for additional server requirements. The object model of the page allows you to dynamically change any aspect of the content (including additions, deletions, and moves).

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

Why is XML so important?

XML will become the future of the computing world. As a technology, its impact will permeate every aspect of programming, from embedded systems to graphical interfaces to distributed systems and database management. It has actually become the standard of data communication between software industries, and quickly replaces EDI systems as the main media for business exchanges in almost all industries worldwide. It is likely to become the language that creates and stores most documents, whether on the Internet or the Internet application Server, and some believe it will replace many of the smaller packaged products currently in production.

What XML products does Microsoft provide?

Microsoft is working to develop XML resources for many areas:

Data access. The latest ActiveX? The Incarnation of Data Objects (ADO) has supported the generation and consumption of XML for nearly a year, and Microsoft SQL Server 2000 provides many interfaces for mutual conversion between sql-based information and XML.

Browser support. Microsoft is the first company to produce a commercial browser (Internet Explorer 5) that can read XML files, whether in the form of an original structure or through an XSL or CSS style sheet.

BizTalk Server 2000. Microsoft? BizTalk (TM) Server 2000 provides a way to communicate across a large number of different formats, including XML, to help drive business-aligned applications. BizTalk Server also includes a number of schema generation and mapping tools that greatly simplify the development of XML structures for business or business needs.

Transfer on the WEB, must compress XML?

In general, the need to compress XML is related to the application and is largely a function of the amount of data moved between the server and the client. The iterative nature of the markup that describes the data structure, enabling XML to compress data very well. It is worth noting that HTTP 1.1 server and client compression are standard and that XML can benefit automatically from it.

How secure is XML as a data format? Is there a plan to increase XML security?

XML is as secure as HTML. Because secure HTTP (HTTPS) can be used to add cryptography to HTTP, which protects HTML, it can also be used to protect XML. XML is a text-based format for representing structured data. This can maximize the simplicity and interoperability of your data. There are a number of steps you can take to add security and validation to your XML format. First, XML can be encrypted on the server before it is transmitted to the customer, and then decrypted on the client. The digital signature applied to the data itself can also validate the XML.

Confirm

What is a DTD and what is its purpose?

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 used in XML documents.

Do WEB developers have to include DTDs when they use XML to describe data?

No. XML can be used to describe data that has or does not have a DTD. The term "valid" XML refers to XML data that references DTDs, while well-formed XML is XML that is not using DTDs. In addition, "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 conform to the standard of the language (for example, all tags must be closed and the tags cannot overlap).

What is an XML schema? What is the difference between them and the DTD?

Although XML 1.0 provides a mechanism for defining the content model of an XML document-dtd-, it is clear that a more comprehensive and efficient approach to defining the content model is needed. An XML Schema is a definition of a particular XML structure (from two aspects of its organization and data type). XML Schemas use the XML Schema language to specify how each type of element is defined in the schema, and the data types associated with the element. The most striking feature of architecture, compared with DTDs, is that the architecture itself is an XML document. This means that the tool that reads the XML it describes can also read it.

Microsoft's XML services currently support the XML data architecture, which represents a snapshot of the "All-in-your-the-system" activity during the March 1999 Internet Explorer 5 shipment. The XML data schema allows developers to add data types to their XML documents, as well as to define open content models. This extension of the DTD functionality is critical to XML programming.

But the consortium is preparing the XML Schema Definition (XSD), which becomes the XML Schema standard. Microsoft plans to make the support for XML Schema Definition (XSD) a part of its core XML service 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 the list of the XML 1.0 specifications as part of the specification in the field. They allow developers to qualify element names and relationships. Namespaces make element names uniquely identifiable, avoiding the same name, but name collisions between elements defined in different dictionaries. They allow you to mix tags from different namespaces, which is important for data from multiple sources.

Namespaces help to define this distinction clearly.

XSLT and XPATH

What is XSLT?

XSLT (English), or Extensible Stylesheet Language for conversion, was approved on November 6, 1999 by the Consortium's recommendations. In both markup and programming terms, this language provides a mechanism for converting an XML structure to another XML structure, 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 actual function of XSLT is to be able to change the underlying structure rather than simply changing the media representation of those constructs, as in cascading style sheets (CSS).

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

XSLT derives from the limitations of CSS on changes to the structure of XML documents, and the reason for creating XML is that it prefers to replace HTML rather than provide a generic data description language. Extensible Stylesheet Language (XSL) is therefore the result of constructing a new method of formatting XML.

However, members of the "Business style work" group and early XML adopters quickly discovered that the ability to convert XML from one format to another can greatly simplify the amount of code generated. Microsoft submitted a proposal to the consortium, originally named XML Query Language (or XQL), which was subsequently adopted by the consortium as the XSL schema language. Most of the functionality of the language is eventually incorporated into the XSLT specification.

The final standard combines XSLT parameters modified for different initial conditions, creating a named template for code feature blocks, and a large number of enhancements for numeric and string processing. XSLT also facilitates the addition of built-in features to the language, offering products that Microsoft can use in its own implementation to add many extremely useful features, 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. XPath allows you to retrieve the collection of elements by specifying a directory-like path (that is, a name) and a condition in the path. XPath is important for both XSLT and XML DOM, and is associated with the XPointer specification, which allows you to select a document fragment based on a combination of Uniform Resource Locator [URL] and XPath expression.

Why is XSLT important to XML?

XSLT is the translation of an XML document into another language. This means that it provides a mechanism for Single-source XML data that can be created in a Web page by creating a rich view of user dynamic changes that can filter data for target traffic. XSLT is strong enough for business rule coding. It can generate graphics from data (not just Web pages). It can even handle communication with other servers-especially the scripting modules that can be integrated into XSLT-and generate the appropriate messages within the XSLT itself. While it is not possible to replace most interactions in desktop systems (both for performance and ease of use), XSLT is likely to eventually become the primary "programming" language for communication between systems over the next few years.

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

The task of cascading style sheets (CSS) is to specify 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.

XSLT, on the other hand, is also called a template-based language, which allows you to map a pattern to a source document whose output is written in XML, HTML, or plain text. Using XSLT, you can convert the structure of an XML document to a different XML document. For example, you can change the order of XML documents, add or delete elements, perform conditional tests, or iterate through 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 XML into a structure such as a list or table, 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.

Standard

How is Microsoft compatible with XML standards?

Starting from the XML language, Microsoft is at the forefront of XML, and it is noteworthy that most of the XML recommendations and work drafts generated by the consortium over the past few years include input and participation from at least one (and possibly several) Microsoft employees. Microsoft has been tasked with many times to work with the consortium to ensure that XML development benefits all users and makes important contributions to development in many different areas, including XML specifications, DOM, XSLT, and schema definition languages. Microsoft is committed to keeping the latest specifications and standards in line.

What is the relationship between XML and the world Wide Web Consortium?

The consortium has an active XML workgroup. Microsoft has been one of the co-sponsors of the organization since June 1996, and since then many industry companies have joined, including Netscape Communications Corp., IBM and Oracle. For more information about the XML standard procedure, visit the Web site of the consortium.

How does XML and the status of the consortium relate?

XML 1.0, which was formally approved in December 1998, is still a stable standard. For more information about the current XML specification and for the submit and review process within the consortium, see the Web site for the consortium.

What is the status of DOM in the consortium?

The status of the 1-per-document is "recommended." This means that the consortium is currently proposing to use it as a standard on the world Wide Web. For more information about the DOM and the process of submitting and reviewing within the consortium, see DOM Specification (English).

Tool support

Does SQL Server and ADO support XML?

Microsoft ActiveX Data Object (ADO) technology, which provides many ways to convert a database recordset (a  records) to XML format, and get the XML from a given structure and convert it back to the database supported by ADO (including SQL Server and Oracle numbers According to the Library) tool. In addition, you can load arbitrary XML directly into ADO to generate a recordset through the XML data source objects in MSXML2 and MSXML3.

SQL Server 2000 also allows you to set up and retrieve XML directly through 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, where you can basically integrate SQL Server data wherever there are XML documents. 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 allow you to map between any number of different data sources (from XML documents to databases to Excel and Word documents), create complex data pipelines for the WEB architecture, and construct an effective schema based on the requirements of your XML database.

Is there a Microsoft tool that can help me quickly use XML?

Microsoft BizTalk Server 2000 is an xml-based server for Data interchange, which provides the basic structure and tools to enable the e-business business community. BizTalk Server is based on a rule-based business document routing, transformation, and tracking infrastructure. This infrastructure allows companies to integrate, manage, and automate business processes by exchanging business documents, such as purchase orders and invoices, within or between applications in an organization's boundaries. For more information, see Microsoft BizTalk Server 2000 (English).

What is SOAP?

SOAP is a Simple Object access Protocol, a tool for creating a wide range of distributed, complex computing environments that can be run on the Internet using an existing Internet infrastructure. SOAP enables applications to communicate with each other directly on the Internet in many ways. For more information about SOAP, see SOAP Specification (English).

How does XML apply to Microsoft Windows? Distributed InterNet Applications (Windows DNA) policy to construct three-tier and WEB-enabled applications?

XML is rapidly becoming a tool for transferring structured data from the middle tier to the desktop. Xml-based data can be integrated with a variety of back-end (database) sources through a middle-tier broker. Schemas (see the "XML Data" section) can improve the process, and developers can more accurately describe and exchange data.

Problems and Solutions

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

By default, the operation is loaded asynchronously. This means that if an HTTP URL address is provided, then the load () method returns directly and the Document object remains empty because the data has not yet been returned from the server. To correct this problem, add the following line to your code:

Xmldoc.async = false;

Also, if you are loading an HTTP XML document from a stand-alone C + + application, you must query the message queue to continue loading.