Removing specific items from array with MongoDB

Question

I am developing a web app using Codeigniter and MongoDB. The users can upload files and other users can comment on them.

I store the comments in an array called comm

Answer 1

If you can identify the comment item by matching userid, name or comment -- then you can remove that comment using update() command with $pull modifier along with the appropriate condition.

If you cannot do as above, include an unique id in the comments (like UUID).

To delete the comment, do the following:

db.coll.update({<cond to identify document}, {$pull: {'comments': {'name': <name>}}} )

If you use the id, which is preferred:

db.coll.update({<cond to identify document}, {$pull: {'comments': {'id': <id>}}} )

Answer 2

maybe you can remove comment by its 'created_at' time, as the time is unique.

$db.coll.update({cond to identify document},{$pull:{'comments':{'created_at':<>}}})

Answer 3

I think, you have add mongodb id to each comment when insert it. You can create a new mongodb id like this;

$comment_id = new MongoID();

Now, you can delete comments by id with $pull + $update like @smoorthy's answer.