#Delphi xml iterate nodes for free#

You can add comments within markers, which are basically ignored by XML processors.It is important to format an XML document to make it readable by a human being, but your programs won't care much. White space (including the space character, carriage return, line feed, and tabs) is generally ignored (as in an HTML document).Here is a short summary of the key elements of the XML syntax:

Core XML SyntaxĪ few technical elements of XML are worth knowing before we discuss its usage in Delphi. The good news is that XML compresses well, for the same reason. (For example, when you have a quantity, you have to agree on the measurement system or include it in the document.) Another disadvantage is that XML documents are much larger than other formats using strings for numbers, for example, is far from efficient, and the repeated opening and closing tags eat up a lot of space. If you want to exchange documents with another company, you must agree on what each tag means and also on the semantic meaning of the content. The biggest is that without a formal description, a document is worth little. XML has a few disadvantages I want to underline from the beginning. Here is an example, in case you've never seen an XML document: The important characteristic of XML is that it is descriptive, because every tag has an almost human-readable name. The XML Recommendation is at XML has been touted as the ASCII of the year 2000, to indicate a simple and widespread technology and also to indicate that an XML document is a plain-text file (optionally with Unicode characters instead of plain ASCII text). The XML language is a standard promoted by the World Wide Web Consortium (W3C).

#Delphi xml iterate nodes for free#

It is extensible because it allows for free markers (in contrast, for example, to HTML, which has predefined markers). XML is a markup language, meaning it uses symbols to describe its own content-in this case, tags consisting of specially defined text enclosed in angle brackets. Introducing XMLĮxtensible Markup Language (XML) is a simplified version of SGML and is getting a lot of attention in the IT world. In Chapter 23, I'll focus specifically on web services and SOAP. Because XML knowledge is far from widespread, I'll provide a little introduction about each technology, but you should refer to books specifically devoted to them to learn more. In this chapter, I'll discuss the core XML technologies and the extensive support Delphi has offered for them since version 6. The emerging standards for this type of activity center around the XML document format and include the SOAP transmission protocol, XML schemas for the validation of documents, and XSL for rendering documents as HTML. From an XML Document to a ClientDataSetīuilding applications for the Internet means using protocols and creating browser-based user interfaces, as you've done in the preceding two chapters, but also opens an opportunity for exchanging business documents electronically.From a ClientDataSet to an XML Document.Direct XSL Transformations with the DOM.Internet Express First Demo (IeFirst.exe).