There’s a lot of excitement about XML
Original article date: October 2000
…if you’re about to specify a format for the file to store the values of a set of parameters, you’d be wise to specify XML…
There’s a lot of excitement about XML at the moment. There’s a lot of rubbish spoken about it too. So I thought it best to dispel a few myths.
XML (Extensible Markup Language) is a file format, pure and simple. It is not a programming language. It is not intended to take over from HTML as the basic form for a web page to be written in. It cannot cure obesity and it will not replace cash by the year 2002.
What it is intended for is to allowing passing of information between programs. There are a few key points about XML:
- It is a well defined standard, so everyone agrees what it looks like (unlike, say, a text file or an RS232 cable!)
- It is totally non platform specific. An XML file produced on a PC is still an XML file when read on a Macintosh
- It acts as a basic, simple layer onto which people can choose to build more complicated file structures.
What all this means is that I can say to a programmer: “The value you want is in the variable called FREQUENCY in the setup file SETUP.XML,” and know that he/she won’t need any further explanation of the file format. What is more, this programmer won’t have to write any new code to deal with this – XML reading/writing code libraries all exist already.
Who cares? Well, as regular readers of my ranting will have heard me say, the useful future of business-to-business e-commerce is not ‘click here to buy’. Instead, my purchasing software will send an order direct to your selling software, and your software will send a confirmation back. It won’t matter that my purchasing software is written by a different lot to your software, because we will all agree what an order looks like. And the order will be in XML. Of course, XML is only the start. It needs people working on standardisation so we agree what fields will be present within the XML file, but that is all happening as we speak.
Other examples of formats built on XML that could become real in the future might include:
- A non vendor specific format for exchanging documents – the Rich Text Format that some word processors use is surprisingly similar to XML
- A non vendor specific format for exchanging engineering drawings.
Another great use of XML is for passing data to web pages via the net. For example, a server somewhere might serve a weather report in XML form to a web page, and the web page – with appropriate use of Javascript or similar – will format the data and present it. This means several different web pages can use the same served data but present it differently, and so the provider of the weather report data need not worry about how the data is to be presented on each web page – the data need only simply be made available as a series of values. The provider and the presenter of the data might be two completely different companies. The provider might sell the data on to the presenter. Or the presenter might be a distributor, offering a subset of products for sale from the manufacturer’s database. Or, in the example above, one national website could choose to combine into a single map data gathered from a multitude of different regional weather measurement centres.
Right now, the crucial things you need to know about XML are as follows:
- It is not going to go away!
- If you are about to specify a format for a file which will store the values of a set of parameters, and which may be shared with other applications, you’d be wise to specify XML
- If you are making a long term purchasing decision regarding software that will handle key commercial data you might wish to communicate with suppliers or customers, then ensure that this aspect is covered.
October 2000