MongoDB::command
(PECL mongo >=0.9.2)
MongoDB::command — Execute a database command
Descrierea
$command
[, array $options = array()
[, string &$hash
]] ) : arrayAlmost 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);
}
?>
Parametri
-
command -
The query to send.
-
options -
An array of options for the index creation. Currently available options include:
-
"socketTimeoutMS"Această opțiune specifică limita de timp în milisecunde pentru comunicarea prin socket. Dacă serverul nu răspunde în limita intervalului de timp, se va emite o MongoCursorTimeoutException și nu va fi nici o posibilitate de a determina dacă serverul a efectuat înscrierea, sau nu. Valoarea
-1poate fi specificată pentru a suspenda pentru o perioadă nedefinită. Valoarea implicită pentru MongoClient este30000(30 secunde).
The following options are deprecated and should no longer be used:
-
"timeout"Un pseudonim învechit pentru
"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().
Istoricul schimbărilor
| Versiune | Descriere |
|---|---|
| PECL mongo 1.5.0 |
Renamed the
Added |
| PECL mongo 1.2.0 |
Added options parameter with a single option:
"timeout".
|
Valorile întoarse
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.
Exemple
Example #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";
}
?>
Exemplul de mai sus va afișa ceva similar cu:
4
22
87
Example #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";
}
?>
Exemplul de mai sus va afișa ceva similar cu:
22
87
Example #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";
}
?>
Exemplul de mai sus va afișa ceva similar cu:
User 47cc67093475061e3d9536d2 had 3 sale(s).
User 49902cde5162504500b45c2c had 14 sale(s).
User 4af467e4fd543cce7b0ea8e2 had 1 sale(s).
Notă: 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.
Notă: The
outargument
Before 1.8.0, the
outargument 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+, theoutargument is required. See the » MapReduce documentation for more information.
Example #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);
?>
A se vedea și
- 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.
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