Let and For clause
Let and for clauses enable the binding of variables to results of any XQuery expressions, whereby, as shown in the further course, the results of path expressions are…
The predicate evaluation
The following pages are from the German book "XQuery – Grundlagen und fortgeschrittene Methoden" (XQuery – basics and advanced methods). The…
Binding of several variables
In a FLWOR expression it is possible to bind simultaneously several variables by a let or a for instruction.
let $x := ..., $y := ... for $x…
Brief vita
Mehrschad Zaeri Esfahani has studied Computer Science (Dipl.-Inform. FH) and Philosophy (Ethikum for engineers) at the Karlsruhe University of Applied Sciences. After…
Explicit type testing
As a further property of the for and let clauses, there is the possibility to perform a type testing via an explicit type declaration by means of the additional key…
Where clause
Analogous to the SELECT-FROM-WHERE block in a SQL query, the where clause of XQuery enables the filtering of the data streams. If the expression of a where…
Order-by clause
The order in which the return clause of a FLWOR expression is evaluated with the appropriate variable allocation can be explicitly enforced by the sorting clause order by.…
Cancellation of the sorting
If, from the view of the application, a sorting is completely refused, it can be communicated to the system with the help of the fn:unordered() function.…
Return clause
The return clause of a FLWOR expression indicates to some extent the template according to which the result document shall be constructed. An important point to…
Nesting of FLWOR expressions
For the illustration of nested FLWOR expressions in return clauses, the query pattern of the pivoting of XML documents is used as an example. Concretely, a…