Setting find conditions to equal a value 2 tbl joins away

Rails
1

ok here is my initial table setups:

ITEM TYPES
id
name

ITEMS
id
name
item_type_id

TOOLS
id
item_id
parent_id

class Tool < ActiveRecord::Base
belongs_to :item

def name
  item.name
end

def item_type
  item.item_type.name
end

end

class Item < ActiveRecord::Base
belongs_to :item_type
end

I can use the following tool.item_type or item.item_type.name to get
the name of the item type but i can not get this query to work:

@tools = Tool.find(:all, :include => :item, :conditions => { :item_type
=> “Instrument”}, :order => :name)

I am getting Unknown column ‘tools.item_type’ even though item_type is
defined in the model. any ideas?

thanks!

2

On 21 May 2008, at 00:05, Scott K. wrote:

end
{ :item_type
=> “Instrument”}, :order => :name)

I am getting Unknown column ‘tools.item_type’ even though item_type is
defined in the model. any ideas?

conditions need to reference database columns. methods you’ve defined
don’t count.
:conditions => {‘items.item_type’ => ‘Instrument’} should work.

Fred

3

Frederick C. wrote:

On 21 May 2008, at 00:05, Scott K. wrote:

end
{ :item_type
=> “Instrument”}, :order => :name)

I am getting Unknown column ‘tools.item_type’ even though item_type is
defined in the model. any ideas?

conditions need to reference database columns. methods you’ve defined
don’t count.
:conditions => {‘items.item_type’ => ‘Instrument’} should work.

Fred

ah ok thanks. since item_type isn’t directly a database column but
item_type_id is i can get this statement working:
@tools = Tool.find(:all, :include => :item, :conditions =>
{‘items.item_type_id’ => 2}, :order => :name)

but what if i want to go one level deeper like

@tools = Tool.find(:all, :include => :item, :conditions =>

{‘items.item_types.name’ => ‘Instrument’}, :order => :name)

or

@tools = Tool.find(:all, :include => :item, :include => :item_type,

:conditions => {‘item_types.name’ => ‘Instrument’}, :order => :name)

the first give me an error saying Unknown column ‘items.item_types.name’
the second gives me the error Association named ‘item_type’ was not
found.

thanks for the help so far. i think i’m almost there!

4

On 21 May 2008, at 00:46, Scott K. wrote:

or

@tools = Tool.find(:all, :include => :item, :include => :item_type,
:conditions => {‘item_types.name’ => ‘Instrument’}, :order => :name)

the first give me an error saying Unknown column
‘items.item_types.name’
the second gives me the error Association named ‘item_type’ was not
found.

There’s 2 separate things going on here. The first is including/
joining the right tables (by the way, do you need :include or
is :joins enough)
if you need to join item and then join item_types onto that then you
need to do :include => {:item => :item_type}.
The second bit is the condition, where you just need to provide the
disambiguated column name ie {‘item_types.name’ => ‘Instrument’}

Fred