mirror of
https://github.com/sigmasternchen/php-doc-en
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83d670adaa
git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@296798 c90b9560-bf6c-de11-be94-00142212c4b1
98 lines
2.4 KiB
XML
98 lines
2.4 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<section xml:id="mongo.updates" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
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<title>Updates</title>
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<para>
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Updates can be one of the the most complicated operation available with
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MongoDB. They combine a query with an action, modifying documents that match
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the criteria. They are also extremely powerful, allowing you to change
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documents quickly and replace them altogether. They are done in-place (when
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possible) with little overhead.
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</para>
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<section>
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<title>Updating Nested Objects</title>
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<para>
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Suppose we wish to change the name of a comment's author in this document:
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<programlisting>
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<![CDATA[
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{
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"_id" : ObjectId("4b06c282edb87a281e09dad9"),
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"content" : "this is a blog post.",
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"comments" :
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[
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{
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"author" : "Mike",
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"comment" : "I think that blah blah blah...",
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},
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{
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"author" : "John",
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"comment" : "I disagree."
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}
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]
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}
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]]>
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</programlisting>
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In order to change an inner field, we use $set (so that all of the other
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fields are not removed!) with the index of comment to change:
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<programlisting role="php">
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<![CDATA[
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<?php
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$blog->update($criteria, array('$set' => array("comments.1" => array("author" => "Jim"))));
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?>
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]]>
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</programlisting>
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</para>
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</section>
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<section>
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<title>The Positional Operator</title>
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<para>
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The positional operator <literal>$</literal> is useful for updating objects
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that are in arrays. In the example above, for instance, suppose that we did
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not know the index of the comment that we needed to change, merely that we
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needed to change "John" to "Jim". We can use <literal>$</literal> to do so.
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</para>
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<programlisting role="php">
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<![CDATA[
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<?php
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$blog->update(
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array("comments.author" => "John"),
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array('$set' => array('comments.$.author' => "Jim")));
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?>
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]]>
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</programlisting>
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</section>
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</section>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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indent-tabs-mode:nil
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sgml-parent-document:nil
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sgml-default-dtd-file:"~/.phpdoc/manual.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:nil
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sgml-local-ecat-files:nil
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End:
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vim600: syn=xml fen fdm=syntax fdl=2 si
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vim: et tw=78 syn=sgml
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vi: ts=1 sw=1
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-->
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