Update Module

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| '''Summary'''
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|This function can be used to both perform updates and return results in a single query. The argument of the function will be evaluated, and the resulting items will be cached and returned after the updates on the ''pending update list'' have been processed. As nodes may be updated, they will be copied before being cached.<br/>The function can only be used together with [[XQuery Update#Updating Expressions|updating expressions]]; if the function is called within a transform expression, its results will be discarded.
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|This function is a helper function for returning results in an updating expression. The argument of the function will be evaluated, and the resulting items will be cached and returned after the updates on the ''pending update list'' have been processed. As nodes may be updated, they will be copied before being cached.
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| '''Examples'''
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Revision as of 09:52, 12 December 2017

This XQuery Module adds updating functions.

Contents

Conventions

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

Output

update:output

Updated with Version 9.0: formerly db:output.

Signatures update:output($result as item()*) as empty-sequence()
Summary This function is a helper function for returning results in an updating expression. The argument of the function will be evaluated, and the resulting items will be cached and returned after the updates on the pending update list have been processed. As nodes may be updated, they will be copied before being cached.
Examples
  • update:output("Prices have been deleted."), delete node //price deletes all price elements in a database and returns an info message.

update:output-cache

Updated with Version 9.0: formerly db:output-cache.

Signatures update:output-cache() as item()*
Summary Returns the items that have been cached by update:output. It can be used to check which items will eventually be returned as result of an updating function.
This function is non-deterministic: It will return different results before and after items have been cached. It is e. g. useful when writing unit tests.

Changelog

This module was introduced with Version 9.0.

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