Tamino XQuery User Guide - Software AG Documentation

The Nuts and Bolts of XQuery
(1, 2, "a", "b", "c", 3, 4)
■ Sequences may contain duplicates.
(input()/bib/book/author/first, input()/bib/book/author/last, ↩
input()/bib/book/author/first)
(1, 2, 3, 4, 3, 2, 1)
Now that there is an order on a sequence, sequence items may occur more than once in a sequence.
These duplicates can have the same value or the same node identity.
Note: In XPath 1.0, a node could only appear once in a node set.
Remember that every expression in XQuery evaluates to a sequence. Even if we have an XQuery
expression such as
let $x := 5
return $x * 30
that defines a local variable $x and returns its value multiplied by 30, the XQuery expression,
strictly speaking, returns a sequence with the single integer value 150.
In contrast to the let variable the type of the sequence for other expressions is constrained to be
a special sequence. For example, a for variable is always an item (identical to a singleton sequence):
for $bib in input()/bib
return $bib
Note: In XQuery, all keywords are written in lower case. It results in a parsing error if you
use mixed or upper case.
Retrieving Data
In Tamino XQuery, there are two functions that provide access to data stored in a Tamino database.
The function input() takes no parameters and is an implementation-defined method to assign
nodes from a source to the input sequence which is evaluated in a query expression. In Tamino, it
is always the current collection of a Tamino database that input() provides access to. The input
sequence then consists of all document nodes of the current collection. Similarly, you can use the
function collection() to access nodes from a collection that may be different from the default
collection. The collection is specified as parameter.
XQuery User Guide
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