MongoDB::commandExecute a database command
&reftitle.description;
publicarrayMongoDB::commandarraydata
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 the function:
selectCollection('$cmd')->findOne($data);
}
?>
]]>
&reftitle.parameters;
data
The query to send.
&reftitle.returnvalues;
Returns database response.
&reftitle.examples;
<function>MongoDB::command</function> "distinct" example
Finding all of the distinct values for a key.
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";
}
?>
]]>
&example.outputs.similar;
4
22
87
<function>MongoDB::command</function> MapReduce example
Get all users with at least on "sale" event, and how many times each
of these users has had a sale.
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")));
$users = $db->selectCollection($sales['result'])->find();
foreach ($users as $user) {
echo "{$user['_id']} had {$user['value']} sale(s).\n";
}
?>
]]>
&example.outputs.similar;
User 47cc67093475061e3d9536d2 had 3 sale(s).
User 49902cde5162504500b45c2c had 14 sale(s).
User 4af467e4fd543cce7b0ea8e2 had 1 sale(s).
Using <classname>MongoCode</classname>
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
MapReduce for more
information.
If you are going to be using MapReduce, Prajwal Tuladhar created an API for
Mongo PHP users which provides a nicer interface than the bare command. You
can download it from
Github
and there is a
blog post
on how to use it.
&reftitle.seealso;
MongoDB core docs on database commands.