GoLang MongoDB::command
GoLang replacement for PHP's MongoDB::command
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PHP MongoDB::command
PHP original manual for MongoDB::command
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MongoDB::command
(PECL mongo >=0.9.2) MongoDB::command — Execute a database command
Description
public array MongoDB::command
( array $command
[, array $options = array()
[, string &$hash
]] )
This method is identical to:
<?php
public function command($data) {
return $this->selectCollection('$cmd')->findOne($data);
}
?>
Parameters
-
command
-
The query to send.
-
options
-
An array of options for the index creation. Currently available options
include:
"socketTimeoutMS" This option specifies the time limit, in milliseconds, for socket communication. If the server does not respond within the timeout period, a MongoCursorTimeoutException will be thrown and there will be no way to determine if the server actually handled the write or not. A value of -1 may be specified to block indefinitely. The default value for MongoClient is 30000 (30 seconds).
The following options are deprecated and should no longer be used:
-
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().
Return Values
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.
Examples
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";
}
?>
The above example will output
something similar to:
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";
}
?>
The above example will output
something similar to:
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";
}
?>
The above example will output
something similar to:
User 47cc67093475061e3d9536d2 had 3 sale(s).
User 49902cde5162504500b45c2c had 14 sale(s).
User 4af467e4fd543cce7b0ea8e2 had 1 sale(s).
Note:
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.
Note:
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.
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);
?>
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