MongoCursor::addOption
(PECL mongo >=1.0.4)
MongoCursor::addOption — Adds a top-level key/value pair to a query
说明
public MongoCursor::addOption ( string$key
, mixed $value
) : MongoCursor
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.
WarningIt 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 $document) { /* empty */ }
?>
以上例程的输出类似于：
{
"op" : "query",
"ns" : "demo.demo",
"query" : {
"$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));
?>
User Contributed Notes
There are no user contributed notes for this page.官方地址：https://www.php.net/manual/en/mongocursor.addoption.php