Help with a find

rubyonrails-talk
1

I have a simple one to many relation:

class Precinct   has_many :districts ... end

I would like to find all Precincts that have no districts in a finder. Is that possible?

I also am using the searchlogic gem (very nice) but even with that I could not concoct a one liner to do what I want.

Any ideas would be greatly appreciated!

- PIto

2

I have a simple one to many relation:

class Precinct has_many :districts ... end

I would like to find all Precincts that have no districts in a finder. Is that possible?

You can do that with a left outer join (and then an isnull to filter for rows with no districts)

Fred

3

Frederick Cheung wrote:

4

Pito Salas wrote: [...]

Thanks... I am not sure how to express that as Precinct.find_..... can you say?

In cases like that, I usually find it helpful to write the SQL first, then transform it into ActiveRecord find syntax.

-- pito

Best,