CouchDB modeling for multi-user

Question

I am already excited about document databases and especially about CouchDB\'s simplicity. But I have a hard time understanding if such databases are a viable option for multi us

Answer 1

Multi-user systems do not require relational databases, though RDBMSs are a staple technology for data storage/retrieval for a vast number of (especially CRUD) applications.

If you want to read-up on document/object -oriented, distributed database solutions of yore, search on "Lotus Notes/Domino" (it's a mature technology/product in this area that's good background knowledge in how applications are designed in a document-based paradigm. Classically, it's really good at workflow type applications).

On CouchDB specifically, check out:

http://wiki.apache.org/couchdb/ (this shouldn't be a surprise)

http://seanoc.wordpress.com/2007/10/12/more-on-couchdb/ (easy reading description overview)

http://twit.tv/floss36 (Podcast interview all about CouchDB)

Answer 2

What @micahwittman says. Just a quick addition: Temp views should never be used in a production system, they are for development only. Permanent views can do everything temp views can do and are magnitudes faster.

Answer 3

There was a discussion on the mailing list awhile back that fits this question fairly well. The rule of thumb was to only store data in a document that is likely to change vs. grow. If the data is more likely to grow then you most likely want to store separate docs.

So in the case of a multi-user system one way of implementing ACL based permissions could be to create 'permission docs' that would be a mapping of user_id to doc_id with the appropriate permission indicated.

{
    _id: "permission_doc_1",
    type: "acl",
    user: "John",
    docid: "John's Account Info",
    read: true,
    write: true
}

And your views would be something along the lines of

function(doc)
{
    emit([doc.user, doc.docid], {"read": doc.read, "write": doc.write});
}

And given a docid and userid, checking for permissions would be:

http://localhost:5984/db/_view/permissions/all?key=["John", "John's Account Info"]

Obviously, this would require having some intermediary between the client and couch to make sure permissions were enforced.