Question

I am trying to add a comment to entries into mongodb.
This is what i have so far

$mongo = new Mongo();
$db = $mongo->comedy;
$collection = $db->cartoons;
$obj = array( 
    "title" => "football", array('comment' => 'my comment here'),
    "author" => "joe" 
);

$collection->insert($obj);

which produces this entry

{
 "_id": ObjectId("5059fd31ba76883414000001"),
 "title": "football",
 "0": {
     "comment": "my comment here"
},
 "author": "joe"
}   

my question is this the best way to nest a comment under the entry “football”? or should i be going about it a different way?

this part doesnt seem correct

"0": {
     "comment": "my comment here"
}

update
from the example below, running this gave an error Fatal error: Call to undefined method MongoDB::update()

$mongo = new Mongo();
$db = $mongo->comedy;
$collection = $db->cartoons;

$mongo->comedy->update(array('title' => 'football'), array(
        '$push' => array('comments' => array('content' => 'Yo!', 'author' => $user_id))
));

then when i run it like

$mongo = new Mongo();
$db = $mongo->comedy;
$collection = $db->cartoons;
$obj = array(
    '$set' => array("title" => "football", "author" => "joe"), 
    '$push' => array('comments' => array('content' => 'Yo!'))
);

i get

{
 "_id": ObjectId("505a2493ba76883c08000007"),
 "title": "football",
 "0": {
     "$push": {
         "comments": {
             "content": "Yo!"
        }
    }
},
 "author": "joe"
}   

Answer 1

This is a very typical problem in MongoDB and as a noob it too got me once here is a good structure (you can Google this around):

{
    title: footbal,
    comments: [
        {content: '', author: ObjectId()},
        { // Next comment }
    ]
}

You can then $push to the comments field making all comments be sorted from newest to
oldest.

As a word of caution: You might find this schema a bit restrictive on it’s querying possibilities especially when you want to, in realtime, sort the comments a different way or pick out different types of comments. In this scenario you would use a separate collection to house the comments ideally.

Edit

In PHP you would start off by inserting your document:

$mongo = new Mongo();
$db = $mongo->comedy;
$collection = $db->cartoons;
$obj = array( "title" => "football");
$collection->insert($obj);

And then when a new comment needs to be added just simply $push:

$mongo->comedy->update(array('title' => 'football'), array(
    '$push' => array('comments' => array('content' => 'Yo!', 'author' => $user_id))
));

And that’s the simple method of doing it 🙂

Edit again

$obj = array('$set' => array("title" => "football", "author" => "joe"), '$push' => array('comments' => array('content' => 'Yo!'))));