Are the find_ methods strictly a SQL thing?


#1

I’ve had a number of occasions now where I want to find something in my
model that is not on the primary object. For instance I’ve got a class
Alert that has_one Status. Status has a “label”.

I want to find all of my Alert objects and order the results
alphabetically by status label.

Can I do that without going into SQL? Right now I find myself doing an
Alert.find :all, :joins=>“as a join status s on a.status_id=s.id”,
:order=>“label” (that’s from memory, sorry if there’s any syntax
errors)…

but there’s gotta be a better way?


#2

This is all possible with associations.

Are you sure Alert has_one status? This implies that the alerts table
does not have a status_id column.

If it does, then you want belongs_to :status

Now, this is easy if status has a field called label

@alerts = Alert.find :all, :include =>:status, :order => ‘label asc’

If Status has a label_id column (and there is a Label model, and
Status belongs_to :label) then you’ll have to do a little more work

And by a little, I mean hardly any

@alerts = Alert.find :all, :include =>[{:status => :label]}, :order =>
‘label asc’

This is untested, so if any of this is buggy, let me know and I’ll help
fix it.


#3

Hi Brian,

You are correct, I meant “belongs_to” – there are a fixed number of
Status objects, each with unique ID, and a variable number of Alert
objects each of which points to one of them.

I see that :include is probably what I should be using in situations
like this.
Knew there had to be something :).

Thanks!

D
Brian H. wrote:

This is all possible with associations.

Are you sure Alert has_one status? This implies that the alerts table
does not have a status_id column.

If it does, then you want belongs_to :status

Now, this is easy if status has a field called label

@alerts = Alert.find :all, :include =>:status, :order => ‘label asc’

If Status has a label_id column (and there is a Label model, and
Status belongs_to :label) then you’ll have to do a little more work

And by a little, I mean hardly any

@alerts = Alert.find :all, :include =>[{:status => :label]}, :order =>
‘label asc’

This is untested, so if any of this is buggy, let me know and I’ll help
fix it.