In order to start your XML training journey, you should have a better understanding of XML uses in real world applications. XML has a variety of uses for web, e-business and portable applications. Likewise, web searching and automating web tasks, general applications, metadata applications and pervasive computing are using XML. The XML is synonymous to a catalyst that enables two different applications (like one mobile app and a website) connect, communicate and exchange data without worrying about their hardware settings or operating systems. Thus, the majority of IT progresses and discoveries such as Internet of Things are the result of XML adoption.
If you new to XML coding or have infrequent XML coding and want to take your XML skills to the next step, there are a few topics that you must master in order to become a professional or full-time XML developer. Here are 10 areas that you must learn and master to solve most of average to complex XML problems.
You need to start off with learning XML fundamentals like essential XML syntax (elements, attributes, entity references, etc), XML document validation and XML namespaces. So assuming you already know the basic of XML, here are top 10 topics:
1- Reading, Writing and Modifying XML in Programs
2- Designing XML to Model Application Data
Here you should learn how to use XML to model real-world data and processes. The adoption and use of standard XML components in application designs result in saving work and making things more accessible to wider audiences. It is also related to using XML in data modeling and OO analysis and design. For instance, while building relationship models of entities, you need to know how to use containment, composition and subelements. Another important topic is to know how to model data schemas.
3- Defining and Enforcing Correct XML Usage
Here you learn how to define an XML application dialect. Also, to enforce correct XML syntax, you need to run a few validation checks such as Document Type Definition or DTD validation and schema validation. You also have to know about the naming convention in XML, metadata, validation issues, building blocks etc and their real syntax standardized by XML developers.
4- Designing Document Type Definitions (DTD)
DTD also plays an important role in XML. If you have to check the vocabulary and validity of the structure of XML against grammatical rules then you need to learn about DTD. Here you need to learn about essential DTD markup and how to define Content Models with ELEMENT Declarations or defining attributes with ATTLIST Declarations. You should learn how to use elements, entities and namespaces in conjunction with DTD. For instance, in a project you may need to know how to group elements for reuse.
5- Viewing and Styling XML in Browsers
If you have to make your document or web page look attractive, you have to use Cascading Style Sheets or CSS. Also, XML developers prefer CSS because it is easy to use and easy to learn. Here you try to add some styling like CSS to your XML codes so that they look more user-friendly. Styling an XML documents is quite different than styling a web page. Some of XML-related CSS topics are Selectors, Classes, Styles, attributes, and rules. Initially you may confuse website CSS with XML one; however, you will get good at it over time. For instance, how can we include our CSS file into our XML document? Are including CSS in XML document the same as adding them to an HTML page like using internal, external and inline CSS?
6- Designing XML Schemas
This step is very important for building clean and organized XML documents. If you want to describe and validate the structure and content of XML data, you need to learn XML schemas. There are two areas of XML schemas that are very important: i- Document Structure and ii- Data Types. For Document Structure, you need to know how to use essential structural elements like attribute, simpleType, etc. Then, you move on to learn more about Global and more complex Types.
For Data Types, you should know how to derive Types with extension and restriction or use validation with pattern matching or regular expression. Here you need to master different methods of validations like checking for required fields, etc.
7- Transforming XML with XSL and XPath
In this step, you explore how the eXtensible Stylesheet Language or XSL works. You also need to learn about XSL Transforms or XSLT. The following are few more things to learn:
- Linking a Stylesheet to an XML Document
- Template Text and XSLT Output
- Rendering HTML Using XSLT and CSS
- Applying a Transform in a Web Browser
- Applying a Transform Programmatically
8- Using XML as Web Content
In this step, you use XML in conjunction with display technologies. That means, you use XML with improved HTML for browsers or mobile profiles. Also, one of the reasons that web designers need to test their sites on different browsers is because browsers 'correct' bad HTML in different ways that’s why you have to check browser support for rendering XML or using special-purpose display XML like SVG.
9- Defining XSL Transforms and Translating Data
At this stage, you need to know how to define an XSL stylesheet with elements such as template, value-of, etc. You should learn how to apply template to selected contents and many more or use XPath expressions in "select" and "match" attributes. Take your time here as there are many more topics to learn. Also in XML translating data you will have the freedom to repurpose and re-use data in multiple situations, rather than repeatedly recreating it.
10- Storing and Mapping XML Databases
In this step, you learn how to map XML to a database DDL. Along the way, you build XML from query results or storing XML in the database. Here you should explore XQuery because it is the powerful query language that replaces complex Java or C++ programs with just a few lines of codes. XQuery is also used for searching and querying XML data. XQUERY is easier to maintain than many other alternatives that is why it is important to learn it.
In this article, we discussed 10 key topics for learning XML. All above 10 topics are essential for mastering XML programming in depth. Here is a few more advance topics that you need to know if you like to become an XML specialist: i- Formatting XML Documents with XSL-FO, ii- Using XML to Build Service-Oriented Architectures or SOA, iii- Creating Rich Web Interfaces with AJAX and XML and iv- Build Simple API for XML Parsing or SAX.
Indeed, the use of XML in API development is very common among developers. One of the major benefits of using XML is its API friendly behavior. In order to examine XML uses as API platforms, you need to understand the XML parser functionality. How it reads the XML and identifies the function of each the pieces of the document, and it then makes that information available in memory to the rest of the program.
I hope my article gives you enough info to find your feet in the journey of mastering XML. There are lots of online resources for learning each topic in depth. So use this document as high level XML developer guide.
I like to conclude this article by going over the following 9 reasons that explain why XML is very popular nowadays:
- XML is often used for distributing data over the Internet.
- XML is used in many aspects of web development.
- XML is often used to separate data from presentation.
- XML tags are not predefined like HTML tags are
- XML was designed to carry data - with focus on what data is
- Most XML applications will work as expected even if new data is added (or removed)
- XML stores data in plain text format. This provides a software- and hardware-independent way of storing, transporting, and sharing data.
- XML also makes it easier to expand or upgrade to new operating systems, new applications, or new browsers, without losing data.
- With XML, data can be available to all kinds of "reading machines" like people, computers, voice machines, news feeds, etc.
This tutorial is written by Matt Zand who is the founder of High School Technology Services, DC Web Makers and Coding Bootcamps.He has written extensively on advance topics on web design, mobile App development and blockchain. He is a senior editor at Touchstone Words where he writes and reviews coding and technology articles. He is also senior instructor and developer living in Washington DC. You can follow him on Linkedin.