MongoID find or find_by

ruby mongodb mongoid
Leopd picture Leopd · Jul 10, 2012 · Viewed 10.5k times · Source

The MongoID docs seem to be pretty clear that I should be able to run this and have it work:

Band.find_by(name: "Photek")

but at least with MongoID 2.4.11 this gives me a NoMethodError.

This, on the other hand, works:

Band.find(name: "Photek")

It's easy enough to change find_by to find, but I'm confused what's going on. Is this a case where my gem version is behind the docs, or what?

Answer

user24359 picture user24359 · Jul 10, 2012

The Mongoid docs now show you version 3 by default (it's an RC). You want to look at the docs here for Mongoid 2.

On find vs find_by, this is from the upgrade guide for Mongoid 2 -> 3:

Model.find and model.relation.find now only take a single or multiple ids. Model.first, Model.last also no longer take arguments. For these use Model.find_by instead.

IOW:

Mongoid 2:

Band.find(some_id)
Band.find(name: "Billy Talent")

Mongoid 3:

Band.find(some_id)
Band.find(some_id, some_other_id)
Band.find_by(name: "Billy Talent")

Related questions

What is the length maximum for a string data type in MongoDB used with Ruby?

I wasn't able to find any information on the max length for a string data type in MongoDB on the main mongodb.org site. I'm coming from a relational database background and there are usually max lengths. Thank you!

Read More
Querying last 30 days date range with Mongoid and Ruby?

How do I go about querying a date range (of say the last 30 days from now) with Mongoid and Ruby? I need to end up with an array or hash like the following: { 15 => 300, 14 => 23, 13 => 23 ... 30 => 20 # Goes over into …

Read More
Mongoid or MongoMapper?

I have tried MongoMapper and it is feature complete (offering almost all AR functionality) but i was not very happy with the performance when using large datasets. Has anyone compared with Mongoid? Any performance gains ?

Read More