Bandwidth issues
Another issue is that XML files are relatively large--five to 10 times the size of an equivalent flat file, in Janson's experience. This is due to the tags surrounding each data element. Consequently, it is not suited to situations where a large amount of information is transferred in a batch because an error in one item may result in the whole lot being rejected.
(A characteristic of XML is that a document must be "well formed"--ie, it complies with the basic XML syntax rules--or it isn't XML and is rejected by the parser.) On the other hand, Janson believes XML is ideal for sending data about individual entities (such as a transaction) in near real-time via the Internet.
Peter Boyle, consulting services manager at IT consultancy Kanbay, took up this theme. When sending data via the Internet, there are good reasons for using compression (to reduce the bandwidth requirement) and encryption (for privacy or security).
While it's possible to wrap compressed and encrypted data in XML, there's no advantage--people are sometimes too quick to reject the traditional flat file based exchange of data, he says.
