Changes

There are a few specialties around XQuery Update that you should know about. In addition to the <b>simple expression</b>, the XQUF adds the <b>updating expression</b> as a new type of expression. An updating expression returns a PUL as a result which is able subsequently applied to change the state of a database node, whereas a addressed databases. A simple expression cannot perform any permanent changesand returns an empty or non-empty sequence.