Loraine Lawson spoke with Cliff Longman of Kalido.
Lawson: You responded to a post about Jeff Pollock's ebizQ article criticizing the pervasive use of XML for all manner of data integration. Is XML doing any of this?
Longman: Well, actually the thing we share in common is that XML doesn't solve the problem. I think I picked up most on the use of XML and data integration generally; it's a solution to such a tiny part of the problem, it's almost irrelevant.
Lawson: What part of the problem do you see it as being a good solution for, and where do you see its limits?
Longman: Well, I think the part that it is a good solution for is, if you take an analogy, it's like the electrical supply system. I see XML as a specification for the shape of the plug socket. So, it means if you've got a toaster or an iron and you've got an AC outlet in the wall, you know that your plug is going to be able to fit into the socket in the wall.
I think XML allows that; it's the connection. Now if you happen to take your iron to the UK, where you plug it into the wall, maybe through an adaptor, it's not going to help if the iron blows up because the voltage is different. So I see the XML piece as being the specification for how two software components can talk to one another. What they put in the packets that travel back and forth-so, if one application for example, were to send an XML packet that said, "I've got an industrial customer #123 whose name is General Electric," when it gets to the other end, there is no guarantee that the interpretation of an application on the receiving end is going to mean the same thing.
I think that the limitation there comes in when you can receive a packet of information, you can unpack it, and you can say, "Oh, the thing at the other end sent me a thing that it calls an industrial customer, and it's given me a thing that it calls a customer code, and it calls a customer name. But I don't have any concept of an industrial customer in my system, so I don't know what an industrial customer is, so I have no idea what that maps to in my world." Again, it's like plugging an iron designed to work on 110 volts into a 240 volt supply; you might be able to plug it into the wall successfully, but that doesn't guarantee it will be able to operate properly.
Lawson: I got the feeling Pollock thought people were using XML in ways that it should not be used. That they have a hammer - XML - so everything is a nail.
Longman: That's the point I agree with him on. There were a number of things in that article that I found myself agreeing with, that being one of them. And I've seen a number of systems recently where everything is converted to XML, and what it really means is the conversion to XML just adds another layer of overhead, it doesn't add new value.