Question

I want to write a named scope to get a record from its id.

For example, I have a model called Event, and I want to simulate Event.find(id) with use of named_scope for future flexibility.

I used this code in my model:

named_scope :from_id, lambda { |id| {:conditions => ['id= ?', id] } }

and I call it from my controller like Event.from_id(id). But my problem is that it returns an array of Event objects instead of just one object.

Thus if I want to get event name, I have to write

event = Event.from_id(id)
event[0].name

while what I want is

event = Event.from_id(id)
event.name

Am I doing something wrong here?

Answer 1

As Damien mentions, using a custom scope just to look up by ID isn’t advisable. But to answer your question:

Finding records with named_scope will always return an ActiveRecord::NamedScope::Scope object, which behaves like an array. If there is just a single record returned by your query, you can use the first method to get the ActiveRecord object directly, like this:

event = Event.from_id(id).first
event.name # will work as you expect