OSB & xquery: when use text() or data(...)

Question

Hi all,
I'm a beginner on xquery and I'm wondering when use text() or data(...).
For example I've this simple xml document:
<book>
<author>A</author>
<year>2010</year>
<price currency="CHF" >100.123</price>
</book>
for retrieving attribute value I have to use data(/book/price/@currency)
but for for retrieving tag value I've two possibilities:/book/price/text() or data(/book/price)
Are those two expressions the same ? Or ones is evaluated faster than the others ?

Answer 1

Text() - always returns the String.
data() - accepts a sequence of items and returns their typed values (return type is xs:anyAtomicType). Calling this function is often unnecessary because the typed value of a node is extracted automatically (in a process known as atomization) for many XQueryXPath 2.0 expressions, including comparisons, arithmetic operations and function calls. The most common use case for the fn:data function is in XQuery element constructors.
Regards,
Anuj