How to mix mongodb and a traditional db in Rails?

Question

I am considering using MongoDB (mongo-mapper) for a portion of my rails application. I am not ready to go whole hog MongoDB because there are too many useful gems that depend on a traditional DB.

That being said there are parts of my application that would be great to leverage a document database.

Has anyone had success mixing the two approaches? How do you link activerecord models with mongomapper models?

Which gems are you thinking of? I am currently migrating my app from MySQL to MongoDB. I was thinking of doing a hybrid approach like yours, but the more I learned about MongoDB the more I realized that I would have huge benefits (in my case) for just migrating everything. Some of the gems you wish to leave behind might actually not be necessary in the NoSQL world. — Chris Garrett, Apr 22 '10 at 12:35
This is what I am using now: acts_as_versioned, formtastic, devise, paperclip, cancan. I *think* a lot of these will need significant tweaking to get to work with mongo — Jonathan, Apr 22 '10 at 12:46
Devise and paperclip both work with Mongoid. Devise used to work with MongoMapper but I think they took it out. I dunno about cancan, but Mongoid has some basic versioning support: http://mongoid.org/docs/extras — MrKurt, Apr 22 '10 at 14:13

score 9 · Accepted Answer · answered Apr 22 '10 at 14:10

9

MongoMapper doesn't implement ActiveModel yet, but I think there are a few forks on github that do. You could use Mongoid instead (which does) and your relationships between Mongoid docs and ActiveRecord entries would just magically work. I know a number of people are doing that.

That said, I wouldn't want to mix them unless I absolutely had to have an RDBMS for some reason.

answered Apr 22 '10 at 14:10

MrKurt

5,080
1
23
22

It looks like that Mongoid implementing ActiveModel makes it seem that it is the way to go. I am going to give it a shot this weekend. I'll report back. Thanks – Jonathan Apr 23 '10 at 18:43
I went with Mongoid, and ported to an all NoSql approach. Pretty happy with the outcome. – Jonathan Apr 28 '10 at 17:47
1

MongoMapper now implements ActiveModel as of version 0.9, according to the current FAQ. – Marnen Laibow-Koser Sep 05 '11 at 21:10

score 3 · Answer 2 · answered Apr 23 '10 at 15:43

3

Here a presentation about this issue: http://nosql.mypopescu.com/post/541657350/presentation-blending-nosql-and-sql-at-confoo

I don't know ROR so I can't judge it is a good presentation.

answered Apr 23 '10 at 15:43

TTT

2,365
17
16

Thanks i'll take a look at that, and post if it was useful. – Jonathan Apr 23 '10 at 18:41

score 2 · Answer 3 · answered Apr 22 '10 at 22:40

2

http://railscasts.com/episodes/194-mongodb-and-mongomapper http://www.mongodb.org/display/DOCS/Object+Mappers+for+Ruby+and+MongoDB http://www.mongodb.org/display/DOCS/MongoDB+Data+Modeling+and+Rails http://www.mongodb.org/display/DOCS/Ruby+Language+Center

You need to mixin mongomapper with the model class This gives you freedom to define the key-value pairs other than activerecord

include MongoMapper::Document

Dead simple I think.

answered Apr 22 '10 at 22:40

Ram on Rails

1,299
11
25

But dont the models have to inherit from MongoID? That is not possible now cause those models are inheriting from AR right? – never_had_a_name Aug 24 '10 at 21:47

How to mix mongodb and a traditional db in Rails?

3 Answers3