MongoCursor::addOption

(PECL mongo >=1.0.4)

MongoCursor::addOption — Adds a top-level key/value pair to a query

说明

public MongoCursor MongoCursor::addOption ( string $key , mixed $value )

This is an advanced function and should not be used unless you know what you're doing.

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:

  <?php

$query  = array( "query"  =>  $query ,  "orderby"  =>  $sort );

 ?>

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.

Warning

It cannot be used to add extra criteria to a query on the fly. For instance, this will not work:

  <?php

 // NOT CORRECT
 $cursor  =  $users -> find ()-> addOption ( "name" ,  "joe" )-> addOption ( "age" ,  20 );

 ?>

This does not query for a user named "joe" with an age of 20.

参数

key: Fieldname to add.
value: Value to add.

返回值

Returns this cursor.

错误／异常

Throws MongoCursorException if this cursor has started iterating.

范例

Example #1 Adding a comment with MongoCursor::addOption() example

MongoDB supports special options to be send to the server. The shell uses the _addSpecial option to send a $comment to the server. This comment will show up in the profiling log (for slow queries f.e.). In the PHP driver, you use the MongoCursor::addOption() method.

  <?php
$m  = new  MongoClient ;
 $c  =  $m -> demo -> demo ;
 $cursor  =  $c -> find ();
 $cursor -> addOption ( '$comment' ,  "This comment will show up in the profiling log" );

foreach ( $cursor  as  $document ) {    }
 ?>

以上例程的输出类似于：

{
    "op" : "query",
    "ns" : "demo.demo",
    "query" : {
        "$query" : {
             
        },
        "$comment" : "This comment will show up in the profiling log"
    },
    "cursorid" : 168463566447,
    "ntoreturn" : 0,
    "ntoskip" : 0,
    "nscanned" : 101,
    "nscannedObjects" : 101,
    "keyUpdates" : 0,
    "numYield" : 0,
…

Example #2 MongoCursor::addOption() example

Using MongoCursor::skip() to skip over millions of results can become slow. One way around this is to use $min or $max 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 $min as an alternative to MongoCursor::skip() .

  <?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 ));

 ?>