TutorialIntroduction
This is the 10gen-supported PHP driver for MongoDB.
Here's a quick code sample that connects, inserts documents, queries for
documents, iterates through query results, and disconnects from MongoDB.
There are more details on each step in the tutorial below.
comedy;
// select a collection (analogous to a relational database's table)
$collection = $db->cartoons;
// add a record
$obj = array( "title" => "Calvin and Hobbes", "author" => "Bill Watterson" );
$collection->insert($obj);
// add another record, with a different "shape"
$obj = array( "title" => "XKCD", "online" => true );
$collection->insert($obj);
// find everything in the collection
$cursor = $collection->find();
// iterate through the results
foreach ($cursor as $obj) {
echo $obj["title"] . "\n";
}
?>
]]>
This would output:
Making a Connection
To connect to the database server, use one of the following:
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You do not have to explicitly disconnect from the database. When
$connection goes out of scope, the connection will be
closed automatically and any database resources it was using will be freed.
See Also
The manual chapter on connecting
covers different types of connections.
The API documentation on the Mongo class and
Mongo::__construct give a comprehensive look at all
possible options with a number of examples.
Getting a Database
To select a database, use:
dbname;
?>
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The database does not need to be created in advance, you can create new
databases by selecting them. Be careful of typos! You can inadvertently
create a new database, which can cause confusing errors:
mybiglongdbname;
// do some stuff
$db = $connection->mybiglongdbnme;
// now connected to a different database!
?>
]]>
See Also
The API documentation on the MongoDB class contains
more information about database objects.
Getting A Collection
Getting a collection has the same syntax as getting a database:
baz;
$collection = $db->foobar;
// or, more succinctly
$collection = $connection->baz->foobar;
?>
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See Also
The API documentation on the MongoCollection class
contains more information about collection objects.
Inserting a Document
Associative arrays are the basic object that can be saved to a collection in
the database. A somewhat random "document" might be:
"MongoDB",
"type" => "database",
"count" => 1,
"info" => (object)array( "x" => 203, "y" => 102),
"versions" => array("0.9.7", "0.9.8", "0.9.9")
);
?>
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Note that you can have nested arrays and objects.
To insert this document, use MongoCollection::insert:
insert( $doc );
?>
]]>
See Also
The API documentation on MongoCollection::insert
contains more information about inserting data.
Finding Documents using <function>MongoCollection::findOne</function>
To show that the document we inserted in the previous step is there, we can
do a simple MongoCollection::findOne operation to get a
single document from the collection. This method is useful when there only is
one document matching the query or you are only interested in one result.
findOne();
var_dump( $obj );
?>
]]>
This should print:
object(MongoId)#6 (0) {
}
["name"]
string(7) "MongoDB"
["type"]=>
string(8) "database"
["count"]=>
int(1)
["info"]=>
array (2) {
["x"]=>
int(203)
["y"]=>
int(102)
}
["versions"]
array(3) {
[0]=>
string(5) "0.9.7"
[1]=>
string(5) "0.9.8"
[2]=>
string(5) "0.9.9"
}
}
]]>
Note the _id field has been added automatically to your
document. _id is the "primary key" field that is
automatically populate for almost all documents in MongoDB.
See Also
The API documentation on MongoCollection::findOne
contains more information about finding data.
Adding Multiple Documents
In order to do more interesting things with queries, let's add multiple
simple documents to the collection. These documents will just be
value );
?>
]]>
and we can do this fairly efficiently in a loop
insert( array( "i" => $i ) );
}
?>
]]>
Notice that we can insert arrays with different key sets into the same
collection. This aspect is what we mean when we say that MongoDB is
"schema-free".
Counting Documents in A Collection
Now that we've inserted 101 documents (the 100 we did in the loop, plus the
first one), we can check to see if we have them all using the
MongoCollection::count method.
count();
?>
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and it should print 101.
Using a Cursor to Get All of the Documents
In order to get all the documents in the collection, we will use
MongoCollection::find. The find() method returns a
MongoCursor object which allows us to iterate over the
set of documents that matched our query. So to query all of the documents and
print them out:
find();
foreach ($cursor as $id => $value) {
echo "$id: ";
var_dump( $value );
}
?>
]]>
and that should print all 101 documents in the collection.
$id is the _id field of a document,
and $value is the document itself.
See Also
The API documentation on MongoCollection::find
contains more information about finding data.
Setting Criteria for a Query
We can create a query to pass to the
MongoCollection::find method to get a subset of the
documents in our collection. For example, if we wanted to find the document
for which the value of the "i" field is 71, we would do the following:
71 );
$cursor = $collection->find( $query );
while( $cursor->hasNext() ) {
var_dump( $cursor->getNext() );
}
?>
]]>
and it should just print just one document
object(MongoId)#6 (0) {
}
["i"]=>
int(71)
["_ns"]=>
"testCollection"
}
]]>
Getting A Set of Documents With a Query
We can use the query to get a set of documents from our collection. For
example, if we wanted to get all documents where "i" > 50, we could write:
array( '$gt' => 50 ) ); //note the single quotes around '$gt'
$cursor = $coll->find( $query );
while( $cursor->hasNext() ) {
var_dump( $cursor->getNext() );
}
?>
]]>
which should print the documents where i > 50. We could also get a range, say
20 < i <= 30:
array( "\$gt" => 20, "\$lte" => 30 ) );
$cursor = $coll->find( $query );
while( $cursor->hasNext() ) {
var_dump( $cursor->getNext() );
}
?>
]]>
As it is easy to forget to escape the "$", you can also choose your own
special character to use instead of '$'. Choose a character that will not
occur in your key names, e.g. ":", and add the following line to php.ini:
Then the example above would look like:
array( ":gt" => 20, ":lte" => 30 ) );
?>
]]>
You can also change it in your code using ini_set("mongo.cmd", ":"). Of
course, you can also just use single quotes around the $.
Creating An Index
MongoDB supports indexes, and they are very easy to add on a collection. To
create an index, you specify the field name and direction: ascending (1) or
descending (-1). The following creates an ascending index on the "i" field:
ensureIndex( array( "i" => 1 ) ); // create index on "i"
$coll->ensureIndex( array( "i" => -1, "j" => 1 ) ); // index on "i" descending, "j" ascending
?>
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