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The MongoDB class

(No version information available, might only be in SVN)

简介

Instances of this class are used to interact with a database. To get a database:

<?php

$m = new Mongo(); // connect
$db = $m->selectDB("example");

?>
Database names can use almost any character in the ASCII range. However, they cannot contain " ", "." or be the empty string. The name "system" is also reserved.

A few unusual, but valid, database names: "null", "[x,y]", "3", "\"", "/".

Unlike collection names, database names may contain "$".

类摘要

MongoDB {
/* 常量 */
const int PROFILING_OFF = 0 ;
const int PROFILING_SLOW = 1 ;
const int PROFILING_ON = 2 ;
/* Fields */
public integer $w = 1 ;
public integer $wtimeout = 10000 ;
/* 方法 */
public array authenticate ( string $username , string $password )
public array command ( array $command [, array $options = array() ] )
public __construct ( Mongo $conn , string $name )
public MongoCollection createCollection ( string $name [, bool $capped = FALSE [, int $size = 0 [, int $max = 0 ]]] )
public array createDBRef ( string $collection , mixed $a )
public array drop ( void )
public array dropCollection ( mixed $coll )
public array execute ( mixed $code [, array $args = array() ] )
public bool forceError ( void )
public MongoCollection __get ( string $name )
public array getDBRef ( array $ref )
public MongoGridFS getGridFS ([ string $prefix = "fs" ] )
public int getProfilingLevel ( void )
public bool getSlaveOkay ( void )
public array lastError ( void )
public array listCollections ( void )
public array prevError ( void )
public array repair ([ bool $preserve_cloned_files = FALSE [, bool $backup_original_files = FALSE ]] )
public array resetError ( void )
public MongoCollection selectCollection ( string $name )
public int setProfilingLevel ( int $level )
public bool setSlaveOkay ([ bool $ok = true ] )
public string __toString ( void )
}

预定义常量

MongoDB Log Levels

MongoDB::PROFILING_OFF
0
Profiling is off.
MongoDB::PROFILING_SLOW
1
Profiling is on for slow operations (>100 ms).
MongoDB::PROFILING_ON
2
Profiling is on for all operations.

Fields

w
1

The number of servers to replicate a change to before returning success. Inherited by instances of MongoCollection derived from this. w functionality is only available in version 1.5.1+ of the MongoDB server and 1.0.8+ of the driver.

w is used whenever you perform a "safe" operation (MongoCollection::insert(), MongoCollection::update(), MongoCollection::remove(), MongoCollection::save(), and MongoCollection::ensureIndex() all support safe options). With the default value (1), a safe operation will return once the database server has the operation. If the server goes down before the operation has been replicated to a slave, it is possible to lose the operation forever. Thus, you can specify w to be higher than one and guarantee that at least one slave has the operation before it is considered successful.

For example, if w is 2, the main server and one slave must have a record of the operation or the driver will throw a MongoCursorException. It is tempting to set w to the total number of slaves + master, but then if one slave is down the op will fail and an exception will be thrown, so usually w=2 is safest (master+1 slave).

wtimeout
10000

The number of milliseconds to wait for MongoDB::$w replications to take place. Inherited by instances of MongoCollection derived from this. w functionality is only available in version 1.5.1+ of the MongoDB server and 1.0.8+ of the driver.

Unless wtimeout is set, the server waits forever for replicating to w servers to finish. The driver defaults to waiting for 10 seconds, you can change this value to alter its behavior.

参见

MongoDB core docs on » databases.

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Core Classes
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PHP手册 - N: The MongoDB class

用户评论:

m dot espositoii at yahoo dot com (27-Aug-2011 11:11)

With Mongo it'll automatically create the collection, so just start using it and it'll do the creation itself.

In other words... just use SelectCollection, if it doesn't exist, it will after that so you can drop it.

jeromakay at yahoo dot com (20-Jan-2011 08:19)

based on what I've read and then applied, you don't have to specifically create a database or table, you just initialize it.

Indeed, files are not being written inside /data/db, but they will the first moment you start adding data.

So, I'm taking as an example Twitter, with no db defined, I'm still going to have the db available if I run this code:

<?php

define('TWITTER_API_VERSION', 1);

date_default_timezone_set("Europe/Dublin");

try
{
    $m = new Mongo(); // connect
    $db = $m->selectDB("example");
}
catch ( MongoConnectionException $e )
{
    echo '<p>Couldn\'t connect to mongodb, is the "mongo" process running?</p>';
    exit();
}

$updates = file_get_contents( "http://api.twitter.com/". TWITTER_API_VERSION ."/statuses/public_timeline.json" );
$updates = json_decode( $updates );

if ( $updates && is_array( $updates ) && count( $updates ) )
{
    foreach ( $updates as $update )
    {   
        $db->users->insert( $update );
    }
}

?>

Hope this was helpful!

Good luck!
Vladimir Ghetau

jonwage at gmail dot com (01-May-2010 07:56)

Just a note that if you use selectDB() and only select it, the database will not be created. In PHPMongoDBAdmin(http://github.com/jwage/php-mongodb-admin) I wanted a way to create a database through a form so I needed to create a dummy collection and drop it in order for the database to be created. MongoDB has a drop() method but no create() method.

<?php
$mongo->selectDB('db')->createCollection('__tmp_collection_');
$mongo->selectDB('db')->dropCollection('__tmp_collection_');
?>

Any better way to do this?