MongoDB commenting system Slug, What is it for?

Question

I'm reading a tutorial on MongoDB on how to model the DB for commenting system in here. One comment document has the following information:

{
    _id: ObjectId(...),
    discussion_id: ObjectId(...),
    parent_id: ObjectId(...),
    slug: '34db/8bda'
    full_slug: '2012.02.08.12.21.08:34db/2012.02.09.22.19.16:8bda',
    posted: ISODateTime(...),
    author: {
              id: ObjectId(...),
              name: 'Rick'
             },
    text: 'This is so bogus ... '
}

What I can't seem to understand is what the slug and full_slug are for, can't understand it from the document.

score 13 · Accepted Answer · answered Oct 21 '12 at 23:34

13

For my opinion, it looks like some kind of a URL shortcut to get the comments, for example, when you type: http://site.com/34db/8bda it will bring you the comment itself, the full-slug is for sorting and ordering the comments by the time they posted.

answered Oct 21 '12 at 23:34

udidu

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Is there a way to generate these slugs? – chovy Oct 29 '12 at 06:14
I found this git, maybe it will help you generating slugs: https://github.com/crowdint/slugoid – udidu Oct 29 '12 at 08:52
IMHO the slug example is too small for real world if it acts as alternative unique key. – Leos Literak Jan 17 '20 at 16:57
The `full_path` slug looks like a [Materialized Path Tree](https://dzone.com/articles/materialized-paths-tree-structures-relational-database) path value. It should be build by using `parent_id` document `full_path` value and adding this document creation date and id. As udidu said, it is used for sorting discussion threads by messages replied to and comment date. – Biapy Jan 05 '23 at 10:53

score 9 · Answer 2 · answered Jan 30 '16 at 12:33

Basically a slug is nothing more than a "part of a URL which identifies" an object "using human-readable keywords" (see Wikipedia "Semantic URL")

In the MongoDB use case document "Storing Comments" each comment gets a unique short "slug part" which can be considered as a kind of alternative, database independent ID. The slug field of the comment document is then built by chaining all slug parts of all comments alongside the discussion thread hierarchy to form a path to the actual comment. Basically it could also be built by joining the string representations of the IDs of all (parent) comments delimited by slashes. But then it would be much longer, less human readable and to some degree more dependent from the underlying MongoDB database.

The full_slug field is formed like the slug as described above but each slug part is prefixed with the date and time of creation of its related comment. This seems to be necessary or at least advantageous to perform sorted queries by discussion thread and date at once. The full_slug field is arranged just for the implementation of queries sorted by discussion thread and date.

score 1 · Answer 3 · answered Mar 20 '14 at 17:05

One thing is like the answer above. But i think they have also another ussage.

For commenting system that required threaded comments (like reply to a comment), you need this "slug" stuffs in order to be able to sort the retrieved comments by 'full_slug'.

Resulted in an array of comments that sorted by threaded order. In the frontend, you can displayed them with different indent.

score 1 · Answer 4 · answered Jan 21 '21 at 01:35

A slug is a human-readable, unique identifier, used to identify a resource instead of a less human-readable identifier like an id . You use a slug when you want to refer to an item while preserving the ability to see, at a glance, what the item is. These identifiers are then used in the URL.

MongoDB commenting system Slug, What is it for?

4 Answers4