MongoDB::command - Execute a database command
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MongoDB::command
(PECL mongo >=0.9.2)
MongoDB::command — Execute a database command
Описание
$command
[, array $options = array()
[, string &$hash
]] )Almost everything that is not a CRUD operation can be done with a database command. Need to know the database version? There's a command for that. Need to do aggregation? There's a command for that. Need to turn up logging? You get the idea.
This method is identical to:
<?php
public function command($data) {
return $this->selectCollection('$cmd')->findOne($data);
}
?>
Список параметров
-
command -
The query to send.
-
options -
An array of options for the index creation. Currently available options include:
"socketTimeoutMS"
Эта опция определяет время в миллисекундах для общения в socket. Если сервер не ответил за отведенное время, то будет брошено исключение MongoCursorTimeoutException, и не будет никакой возможности определить произвел ли сервер запись или нет. Значение -1 используется для постоянно отключения этой функции. Значением по умолчанию для MongoClient является 30000 (30 секунд).
The following options are deprecated and should no longer be used:
"timeout"
Устаревший псевдоним для "socketTimeoutMS".
-
hash -
Set to the connection hash of the server that executed the command. When the command result is suitable for creating a MongoCommandCursor, the hash is intended to be passed to MongoCommandCursor::createFromDocument().
The hash will also correspond to a connection returned from MongoClient::getConnections().
Список изменений
| Версия | Описание |
|---|---|
| 1.5.0 |
Renamed the "timeout" option to
"socketTimeoutMS". Emits
Added hash by-reference parameter. |
| 1.2.0 | Added options parameter with a single option: "timeout". |
Возвращаемые значения
Returns database response. Every database response is always maximum one document, which means that the result of a database command can never exceed 16MB. The resulting document's structure depends on the command, but most results will have the ok field to indicate success or failure and results containing an array of each of the resulting documents.
Примеры
Пример #1 MongoDB::command() "distinct" example
Finding all of the distinct values for a key.
<?php
$people = $db->people;
$people->insert(array("name" => "Joe", "age" => 4));
$people->insert(array("name" => "Sally", "age" => 22));
$people->insert(array("name" => "Dave", "age" => 22));
$people->insert(array("name" => "Molly", "age" => 87));
$ages = $db->command(array("distinct" => "people", "key" => "age"));
foreach ($ages['values'] as $age) {
echo "$age\n";
}
?>
Результатом выполнения данного примера будет что-то подобное:
4
22
87
Пример #2 MongoDB::command() "distinct" example
Finding all of the distinct values for a key, where the value is larger than or equal to 18.
<?php
$people = $db->people;
$people->insert(array("name" => "Joe", "age" => 4));
$people->insert(array("name" => "Sally", "age" => 22));
$people->insert(array("name" => "Dave", "age" => 22));
$people->insert(array("name" => "Molly", "age" => 87));
$ages = $db->command(
array(
"distinct" => "people",
"key" => "age",
"query" => array("age" => array('$gte' => 18))
)
);
foreach ($ages['values'] as $age) {
echo "$age\n";
}
?>
Результатом выполнения данного примера будет что-то подобное:
22
87
Пример #3 MongoDB::command() MapReduce example
Get all users with at least on "sale" event, and how many times each of these users has had a sale.
<?php
// sample event document
$events->insert(array("user_id" => $id,
"type" => $type,
"time" => new MongoDate(),
"desc" => $description));
// construct map and reduce functions
$map = new MongoCode("function() { emit(this.user_id,1); }");
$reduce = new MongoCode("function(k, vals) { ".
"var sum = 0;".
"for (var i in vals) {".
"sum += vals[i];".
"}".
"return sum; }");
$sales = $db->command(array(
"mapreduce" => "events",
"map" => $map,
"reduce" => $reduce,
"query" => array("type" => "sale"),
"out" => array("merge" => "eventCounts")));
$users = $db->selectCollection($sales['result'])->find();
foreach ($users as $user) {
echo "{$user['_id']} had {$user['value']} sale(s).\n";
}
?>
Результатом выполнения данного примера будет что-то подобное:
User 47cc67093475061e3d9536d2 had 3 sale(s).
User 49902cde5162504500b45c2c had 14 sale(s).
User 4af467e4fd543cce7b0ea8e2 had 1 sale(s).
Замечание: Using MongoCode
This example uses MongoCode, which can also take a scope argument. However, at the moment, MongoDB does not support using scopes in MapReduce. If you would like to use client-side variables in the MapReduce functions, you can add them to the global scope by using the optional scope field with the database command. See the » MapReduce documentation for more information.
Замечание: The out argument
Before 1.8.0, the out argument was optional. If you did not use it, MapReduce results would be written to a temporary collection, which would be deleted when your connection was closed. In 1.8.0+, the out argument is required. See the » MapReduce documentation for more information.
Пример #4 MongoDB::command() "geoNear" example
This example shows how to use the geoNear command.
<?php
$m = new MongoClient();
$d = $m->demo;
$c = $d->poiConcat;
$r = $d->command(array(
'geoNear' => "poiConcat", // Search in the poiConcat collection
'near' => array(-0.08, 51.48), // Search near 51.48°N, 0.08°E
'spherical' => true, // Enable spherical search
'num' => 5, // Maximum 5 returned documents
));
print_r($r);
?>
Смотрите также
- MongoCollection::aggregate() - Perform an aggregation using the aggregation framework
- MongoCollection::findAndModify() - Update a document and return it
- MongoCollection::group() - Performs an operation similar to SQL's GROUP BY command
MongoDB core docs on » database commands and on individual commands: » findAndModify, » getLastError, and » repairDatabase (dozens more exist, there are merely a few examples).
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