Php/docs/mongodb.execute
MongoDB::execute
(PECL mongo >=0.9.3)
MongoDB::execute — Runs JavaScript code on the database server [deprecated]
Description
public MongoDB::execute
( mixed $code
[, array $args = array()
] ) : array
Warning The » eval command, which this method invokes, is deprecated in MongoDB 3.0+.
The Mongo database server runs a JavaScript engine. This method allows you to run arbitary JavaScript on the database. This can be useful if you want touch a number of collections lightly, or process some results on the database side to reduce the amount that has to be sent to the client.
Running JavaScript in the database takes a write lock, meaning it blocks other operations. Make sure you consider this before running a long script.
This is a wrapper for the » eval database command. This method is basically:
<?phppublic function execute($code, $args) { return $this->command(array('eval' => $code, 'args' => $args));}?>
MongoDB implies a return statement if you have a single statement on a single line. This can cause some unintuitive behavior. For example, this returns "foo":
<?php$db->execute('"foo";');?>
However, these return NULL:
<?php$db->execute('"bar"; "foo";'); // more than one statement$db->execute('db.foo.count();'); // more than one line?>
To avoid surprising behavior, it is best not to depend on MongoDB to decide what to return, but to explicitly state a return value. In the examples above, we can change them to:
<?php$db->execute('"bar"; return "foo";');$db->execute('return db.foo.count();');?>
Now the first statement will return "foo" and the second statement will return a count of the "foo" collection.
Return Values
Returns the result of the evaluation.
Examples
Example #1 Simple MongoDB::execute() example
<?php$response = $db->execute("function() { return 'Hello, world!'; }");echo $response['retval'];?>
The above example will output something similar to:
Hello, world!
Example #2 Parameter MongoDB::execute() example
The optional array of parameters will be passed to the JavaScript function.
<?php$response = $db->execute("function(greeting, name) { return greeting+', '+name+'!'; }", array("Good bye", "Joe"));echo $response['retval'];?>
The above example will output something similar to:
Good bye, Joe!
Example #3 Scope example
If a MongoCode object is used instead of a string for the first parameter, a scope can be passed in which the JavaScript will be executed.
<?php$func = "function(greeting, name) { ". "return greeting+', '+name+', says '+greeter;". "}";$scope = array("greeter" => "Fred");$code = new MongoCode($func, $scope);$response = $db->execute($code, array("Goodbye", "Joe"));echo $response['retval'];?>
The above example will output something similar to:
Goodbye, Joe, says Fred
Changelog
| Version | Description |
|---|---|
| PECL mongo 1.7.0 | This method has been deprecated as a result of the underlaying
» eval command being deprecated in MongoDB 3.0+. |
