php-doc-en/reference/mongo/mongocollection/deleteindex.xml

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<refentry xml:id="mongocollection.deleteindex" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
 <refnamediv>
  <refname>MongoCollection::deleteIndex</refname>
  <refpurpose>Deletes an index from this collection</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <modifier>public</modifier> <type>array</type><methodname>MongoCollection::deleteIndex</methodname>
   <methodparam><type>string|array</type><parameter>keys</parameter></methodparam>
  </methodsynopsis>
  <para>
   This method is identical to:
  </para>
  <programlisting role="php">
<![CDATA[
<?php

public function deleteIndexes($keys) {
  $indexName = $this->toIndexString($keys);

  return $this->db->command(array(
    "deleteIndexes" => $this->getName(),
    "index" => $indexName,
  ));
}

?>
]]>
  </programlisting>
  <para>
   Each index is given a unique name when it is created. This is often generated
   by the driver based on the index key(s) and order/type, but custom names may
   also be specified with <function>MongoCollection::createIndex</function>'s
   <literal>"name"</literal> option).
  </para>
  <para>
   Unfortunately, <function>MongoCollection::deleteIndex</function> cannot
   delete custom-named indexes due to a backwards compatibility issue. When a
   string argument is provided, it is assumed to be the single field name in an
   ascending index (e.g. the name <literal>"x_1"</literal> would be used for the
   argument <literal>"x"</literal>). If an array or object is provided, an index
   name is generated just as if that argument was passed to
   <function>MongoCollection::createIndex</function>.
  </para>
  <para>
   In order to delete a custom-named index with the PHP driver, the
   <literal>deleteIndexes</literal> database command must be used. For instance,
   an index named "myIndex" could be deleted with the PHP driver by running:
  </para>
  <programlisting role="php">
<![CDATA[
<?php

$db->command(array(
  "deleteIndexes" => $collection->getName(),
  "index" => "myIndex",
));

?>
]]>
  </programlisting>
  <para>
   To determine the name of an index with the PHP driver, you can query the
   <literal>system.indexes</literal> collection of a database and look for the
   <literal>"name"</literal> field of each result. The <literal>"ns"</literal>
   field will indicate the collection to which each index belongs.
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term>
      <parameter>keys</parameter>
     </term>
     <listitem>
      <para>
       An array specifying the index's fields as its keys. For each field, the
       value is either the index direction or
       <link xlink:href="&url.mongodb.dochub.indexes.types;">index type</link>.
       If specifying direction, specify <literal>1</literal> for ascending or
       <literal>-1</literal> for descending.
      </para>
      <para>
       If a string is provided, it is assumed to be the single field name in an
       ascending index.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns the database response.
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <example>
   <title><function>MongoCollection::deleteIndex</function> example</title>
   <para>
    This example passes the function string and array parameters.
   </para>
   <programlisting role="php">
<![CDATA[
<?php

$m = new MongoClient();
$c = $m->example->indices;

// create and remove a simple index
$c->createIndex(array("i"=>1));
$c->deleteIndex("i");

// create and remove a multi-key index
$c->ensureIndex(array("j" => 1, "k" => 1));
$c->deleteIndex(array("j" => 1, "k" => 1));

?>
]]>
   </programlisting>
  </example>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <simplelist>
   <member><methodname>MongoCollection::createIndex</methodname></member>
   <member><methodname>MongoCollection::deleteIndexes</methodname></member>
   <member><methodname>MongoCollection::toIndexString</methodname></member>
   <member>
    The MongoDB
    <link xlink:href="&url.mongodb.dochub.indexes;">index</link> and
    <link xlink:href="&url.mongodb.dochub.indexes.types;">index type</link>
    documentation.
   </member>
  </simplelist>
 </refsect1>

</refentry>
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