php-doc-en/reference/mongo/mongocursor/addoption.xml
Kristina Chodorow 2541fdcd88 MongoCursor::addOption
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2010-02-02 21:42:08 +00:00

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<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<refentry xml:id="mongocursor.addoption" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
<refnamediv>
<refname>MongoCursor::addOption</refname>
<refpurpose>Adds a top-level key/value pair to a query</refpurpose>
</refnamediv>
<refsect1 role="description">
&reftitle.description;
<methodsynopsis>
<modifier>public</modifier> <type>MongoCursor</type><methodname>MongoCursor::addOption</methodname>
<methodparam><type>string</type><parameter>key</parameter></methodparam>
<methodparam><type>mixed</type><parameter>value</parameter></methodparam>
</methodsynopsis>
<para>
This is an advanced function and should not be used unless you know what
you're doing.
</para>
<para>
A query can optionally be nested in a "query" field if other options, such as
a sort or hint, are given. For instance, adding a sort causes the query
to become a subfield of a bigger query object, like:
<programlisting role="php">
<![CDATA[
<?php
$query = array("query" => $query, "orderby" => $sort);
?>
]]>
</programlisting>
</para>
<para>
This method is for adding a top-level field to a query. It makes the query a
subobject (if it isn't already) and adds the key/value pair of your chosing
to the top level.
</para>
<warning>
<para>
It cannot be used to add extra criteria to a query on the fly. For instance,
this <emphasis>will not</emphasis> work:
<programlisting role="php">
<![CDATA[
<?php
// NOT CORRECT
$cursor = $users->find()->addOption("name", "joe")->addOption("age", 20);
?>
]]>
</programlisting>
This <emphasis>does not</emphasis> query for a user named "joe" with an age of 20.
</para>
</warning>
</refsect1>
<refsect1 role="parameters">
&reftitle.parameters;
<para>
<variablelist>
<varlistentry>
<term>
<parameter>key</parameter>
</term>
<listitem>
<para>
Fieldname to add.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<parameter>value</parameter>
</term>
<listitem>
<para>
Value to add.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1 role="returnvalues">
&reftitle.returnvalues;
<para>
Returns this cursor.
</para>
</refsect1>
<refsect1 role="errors">
&reftitle.errors;
<para>
Throws <classname>MongoCursorException</classname> if this cursor has started iterating.
</para>
</refsect1>
<refsect1 role="examples">
&reftitle.examples;
<example>
<title><function>MongoCursor::addOption</function> example</title>
<para>
Using <function>MongoCursor::skip</function> to skip over millions of
results can become slow. One way around this is to use
<literal>$min</literal> or <literal>$max</literal> options for the query.
These can be handy, but they require an index on exactly the fields being
searched for. This is an example of how to use <literal>$min</literal> as
an alternative to <function>MongoCursor::skip</function>.
</para>
<programlisting role="php">
<![CDATA[
<?php
// make sure we have an index
$c->ensureIndex(array("ts" => 1));
// you may have to modify this to run in a reasonable amount of time on slow
// machines (should take about 30 seconds on a good machine)
for ($i = 0; $i < 30000000; $i++) {
$c->insert(array("ts" => new MongoDate(), "i" => $i));
}
$now = strtotime("now");
// find documents inserted in the last 2 seconds
$cursor = $c->find()->addOption('$min', array("ts" => $now-2));
?>
]]>
</programlisting>
</example>
</refsect1>
</refentry>
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