XML is an abbreviation for Extended Mark-up Language. Just like HTML, it is a mark-up language, which means it is a way of formatting text. It is important to remember that XML is not an alternative to HTML. It does, however, allow you to add more properties to HTML. While HTML is primarily used for structuring text, XML is made for structuring data.
The following table shows the basic differences between HTML and XML:
| HTML | XML |
|---|---|
| • Structures text | • Structures data |
| • Comes with predefined tags, like and | • Does not come with predefined tags. The programmer needs to define tags |
| • Tags are not case-sensitive. For example, means the same as
or |
• Tags are case-sensitive. For example. |
| • A document needs DOCTYPE, HTML, HEAD, and BODY to function properly | • A document needs DOCTYPE to function properly |
The content of an XML file can be formatted to resemble a website. It can be used and work well for news feeds, but it is not a good option for making regular websites. For ordinary websites, a combination of XML and HTML is the best solution.
There is a language called XHTML, which is a combo of the two languages. To be honest, it should have replaced HTML. In reality, though, it is not used much by programmers. That’s most likely the case because HTML 5 has fixed the weaknesses XML was meant to repair.
The concept of XML databases seems to be rather “anonymous”, and not many people can relate to it. It is, however, used quite a lot. One example of it is a Word document. It is, in fact, a set of XML databases.
Try this: Rename a Word document from .doc to .docx to .zip. This means telling the programs to treat this file as if it were an archive or a compressed file made by WinZip. You can now open the document as a zip file and see the hidden XML files. Those enable the Word document to tell where you want to insert images or where the text is supposed to be bold or italics.
Why Should You Learn to Use XML?
XML plays an important role in multiple IT systems. Distributing data over the Internet is often done utilizing XML. It is, therefore, crucial for all software developers to understand XML well. When it comes to creating websites, it can become necessary to use databases for several purposes. A dictionary search immediately gives you a feeling of looking something up in a database. You may be surprised to learn that web forums and WordPress are also databases. In those cases, though, users cannot see the search and retrieval as they are running in the background.
Advantages of Using XML
There are three main advantages of using XML when it comes to websites:
- Creating small to medium databases with XML is pretty straightforward. Databases have flexible designs for fast lookups on the website.
- The database can be accessed locally on the server as it is placed together with the rest of the website. It is not necessary to use separate or dedicated servers (as required when using SQL databases).
- The databases function independently of third-party programs, such as Access, Lotus Notes, or MySQL. They can be accessed using any browser via JavaScript.
- XML makes things simpler. It makes data availability, sharing, and transport more straightforward. It makes changing platforms easier.
Data format in multiple computer systems may be incompatible. Exchanging data between incompatible or upgraded systems becomes a tedious job. Firstly, big amounts of data have to be converted. Secondly, incompatible data is often lost in the process.
Data in XML is stored in a plain text format, thus making the storing, transporting, and sharing data independent of the software and hardware used.
Thanks to XML, expanding or upgrading to a new OS, applications, or browsers is much easier and doesn’t carry the risk of losing data.
Plain text format makes XML data available to people, computers, voice machines, news feeds, and other “reading machines.”
Disadvantages of XML
There is a couple of drawbacks when it comes to XML. They are:
- You cannot read and write in the database the way you can with an SQL database used for blogs, discussion groups, or comment sections of websites.
- XML works well for small and medium databases. Large databases become slow when accessing the page.
Try this trick: If you still want to use XML for a large database, split it up into several smaller databases. The bottom line is that XML is not the perfect solution for everything. It is, however, a fantastic tool for many jobs and it is worthwhile, or even necessary, for you to learn it.