XQuery Module

This XQuery Module contains functions for evaluating XQuery strings and modules at runtime.

Conventions

All functions in this module are assigned to the http://basex.org/modules/xquery namespace, which is statically bound to the xquery prefix.
All errors are assigned to the http://basex.org/errors namespace, which is statically bound to the bxerr prefix.

Functions

xquery:eval

Signatures	xquery:eval($query as xs:string) as item()* xquery:eval($query as xs:string, $bindings as map(*)) as item()*
Summary	Evaluates $query as XQuery expression at runtime and returns the resulting items. Database nodes in the result will be copied and returned instead. Variables and context items can be declared via $bindings. The specified keys must be QNames or strings, the values can be arbitrary item sequences: variables specified as QNames will be directly interpreted as variable name. variables specified as xs:string may be prefixed with a dollar sign. Namespace can be specified using the Clark Notation. If the specified string is empty, the value will be bound to the context item.
Errors	BXXQ0001: the query contains updating expressions. FOTY0013: the expression yields function items.
Examples	xquery:eval("1+3") returns 4. You can bind the context and e.g. operate on a certain database only: xquery:eval("//country", map{ '' := db:open('factbook') }) The following expressions use strings as keys. All of them return 'XML': xquery:eval(".", map{ '' := 'XML' }) xquery:eval("$xml", map{ 'xml' := 'XML' }), xquery:eval("$xml", map{ '$xml' := 'XML' }), xquery:eval("declare namespace pref='URI'; $pref:xml", map{ '{URI}xml' := 'XML' }), The following expressions use QNames as keys. All of them return 'XML': declare namespace pref = 'URI'; xquery:eval("$xml", map{ xs:QName('xml') := 'XML' }) xquery:eval("declare namespace pref='URI'; $pref:xml", map{ xs:QName('pref:xml') := 'XML' }),

xquery:evaluate

Signatures	xquery:evaluate($query as xs:string) as item()* xquery:evaluate($query as xs:string, $bindings as map(*)) as item()*
Summary	Evaluates $query as XQuery expression at runtime and returns the resulting items. In contrast to xquery:eval, items will never be copied by this function. In exchange, no new database can be opened by this function.
Errors	BXXQ0001: the query contains updating expressions. FOTY0013: the expression yields function items.

xquery:invoke

Signatures	xquery:invoke($uri as xs:string) as item()* xquery:invoke($uri as xs:string, $bindings as map(*)) as item()*
Summary	Opens $uri as file, evaluates it as XQuery expression at runtime, and returns the resulting items. Database nodes in the result will be copied and returned instead. The semantics of the $bindings parameter is the same as for xquery:eval.
Errors	BXXQ0001: the expression contains updating expressions. FOTY0013: the expression yields function items.

xquery:type

Signatures	xquery:type($expr as item()*) as item()*
Summary	Similar to fn:trace($expr, $msg), but instead of a user-defined message, it emits the compile-time type and estimated result size of its argument.

Errors

Code	Description
BXXQ0001	A dynamically evaluated query must not contain any updating expressions.

Changelog

Version 7.8

• Added: [#xquery:evaluate|xquery:evaluate]]

This module was introduced with Version 7.3. Functions have been adopted from the obsolete Utility Module.