Reference Through records in a has many through join

rubyonrails-talk
1

I have 2 tables (toms and dicks) joined with has_many through a third table (harries).

@tom = Tom.find(1)

How do you reference all the related records in harries. If I do:

@tom.dicks[1].harries

I get records for all records in tom, not just for @tom i.e. with an id of 1.

Many thanks,

Mike

2

It depends on what you configured as relations between those objects : I guess you might have something like that : class Tom < ...(whatever ActiveRecord)   :has_many :harries   :has_many :dicks, :througt => :harries end

class Dick< ...(whatever ActiveRecord)   :has_many :harries   :has_many :toms, :througt => :harries end

class Harry < ...(whatever ActiveRecord)   :belongs_to :tom   :belongs_to :dick end

(I'm not really sure of the correctness of what is written but it's not the point)

Let's assume that migrations are ok So what's up @tom, let's say @tom is defined as you proposed @tom= Tom.find(1)

now you can access the dicks of @tom (haha!!) like this @tom.dicks

so if you want a specified one, you can do something like that

@tom.dicks[42] # it will return the 42 Dick instance of the Array represented in @tom.dicks

As this one is an Dick instance, you still have access to his harries, like this @tom.dicks[42].harries

And if you want a specific Harry instance, you may try something like the following Harry.find(:first, :conditions => [ "tom_id = ? AND dick_id = ? ", 1, @tom.dicks[42].id])

Hope it helps

3

Thanks very much for the thorough response. It surprises me that having declared:

@tom= Tom.find(1)

there is not a more direct route to accessing related harries.

Heh ho,

more thanks,

Mike

4

Having declared @tom= Tom.find(1), you can access @tom.harries which is an array of Harry object where tom_id = 1. I though you want to access directly to the related dicks of @tom.

Sorry for misundertanding