I found that Bill Gates gives the simplest explanation of why we should at least have an intuitive understanding of XML.
First a reminder of how the internet and world wide web works
1. The internet is made of networks of networks of computers and computer-like devices like our smart phones.
2. We often (though not always) access information on a computer through webpage on a website.
3. A web page is laid out using HTML. For example, my headings on this page have tags (code) around them that looks like this “<h3>my heading</h3>”.
4. There are two more things we should know about this code. First, the code is not visible to us unless we ask to see it.
5. Second, we put the definition of, that is the size, the colour and the font in another set of code called CSS. The CSS might be at the top or bottom of the web page but is probably in another file. To link up our webpage to that code, we simply put a line of code (invisible unless we ask to see it) telling the webpage where to find the CSS file and what it is called.
And now to why we need XML
If we only intend people to read a web page, then we only need to lay out our page with HTML (to make it look nice) and have a separate CSS (style) file which defines headings and other formats, like fonts, consistently.
But we often want people to use our data as well.
Example of when we want to tag our data with XML
For example, an airline wants me to read its page (so it should look nice and be consistent).
It also wants travel agents to pick up information about its flights and prices and put up-to-date relevant information into their websites.
XML is used to label the data itself (in addition to labelling is style using HTML tags). So the airlines will tag a departure time as , for example. They will tag an airport name as , perhaps.
By tagging the data, another computer knows immediately that some numbers are a departure time or a name is the name of an airport.
Business people need to understand XML
As Bill Gates puts it, “XML ‘unlocks’ data so that it can be organized, programmed and edited”.
Business managers need to understand XML because the need to understand
1. What data is shared in their industry and what the advantages are of doing so
2. How their data can be structured consistently so computers can work with it
3. Where and how XML tags are added so they can plan workflows and maintain systems efficiently
4. How to check and audit XML (unless they want to be taken to the cleaners)
In a later post, I’ll make a simple example of working XML so that you can see what you should be looking out for.