The XQuery language makes it possible for programmers to do much more with XML documents than can be achieved with HTML. For example, an XML document can contain comments, macros, loops, conditionals, types and XML attribute references. This makes XML very flexible but also adds to the complexity of this query language, and many users need help with XML, so that they can develop programs in a more readable manner.
There are many places on the Internet where XQuery programming can be used. One of the most common uses is in creating custom XML plug-ins, allowing you to extend the functionality of certain software programs. In addition, this type of programming can be used to create a database of structured data and then convert it into an XML format, which is then sent to a client application, such as an online shopping cart. or payment gateway. Using the XQuery language you can also create a map of geographic coordinates and associate them with text labels, which can then be used as labels for other applications on a web page.
As you learn to use the XQuery Language, you will learn that there are a number of commands that allow you to insert XHTML attributes and codes directly into the source code of a program. For example, the insertHTML command inserts an HTML tag into the source code, which describes the information you want the source code to display. This allows the developer to modify the existing program without changing the source code itself. The insertXML command inserts an XHTML tag into the source code, and allows you to modify the existing source code as well.
Other features include the following: Insert the XML label into the source code, change the HTML label, insert the XHTML tags into the source code, insert the XHTML keywords into the source code, set the value of the XHTML label, insert the XHTML keywords into the source code, and even change the color scheme of the XHTML tag. XQuery Programming is one of the best languages to learn if you are going to become an XML expert.