The X-factor - XML and XPath injections

Some app developers are eschewing SQL for new, open-standards-based data structures written in XML. Why will someone choose this? Relational databases composed with SQL are certainly leveraging a very stable, mature technology, but sometimes data that has multiple indices of relationships is more compact when rendered and stored in XML. This needs to be balanced against the performance in the database tier. Relational databases differentiate between variable types, which means they can provide optimized treatment of those based on whether they are a string, integer, Boolean, or others. XML treats everything like a string of text, so the burden is on the Application Tier to comb over the stored data and make manipulations with more complex logic and processing overhead. There is no 100% right answer – these factors will be weighed...