Using :include "recursively" (including the children of the

Rails
1

Hi,

Let’s say I have the following hierarchy of tables:

Group <- parent
Location <- child of Group
School <- child of Location
Phone <- child of School

Then, if I want to do this:

Location.find(…someparms…, :include => [:schools, :group, :phones])

I get an association error (Association was not found). I guess it
happens because AR is looking in the Location model for the Phones
association, which only exists in the School model (I also tried
singular, :phone).

Is there any way I can load all Phone records at once? I wouldn’t mind
using custom SQL if that’s the only solution.

Thanks in advance!

Ivan V.

PS: Merrrrry christmas!

2

On Fri, Dec 16, 2005 at 02:14:57PM -0600, Iv?n Vega R. wrote:

Is there any way I can load all Phone records at once? I wouldn’t mind
using custom SQL if that’s the only solution.

There is no way to do that using the eager loading implementation. It
would
require custom SQL.

marcel

3

Marcel Molina Jr. wrote:

Would it be possible to load the phones for the object:

@locs = Location.find(…someparms…, :include => [:schools, :group])

and then something like:

@locs.schools.phones.load_all (of course this method doesn’t exist, but
is there something similar?)

Or could I “find” all the phones that belong to certain schools and then
assign those to the specific @locs.schools object?

Thanks!

Ivan V.

4

If it’s just for the location, then you could include a redundant
foreign
key (has_many) to the phones. Then you could use Location.find(
…someparams :include => [:phones])

Alternativley a method in the Locations model could look something like
for
the current location

def self.get_phones
Phone.find_by_sql(
“SELECT phones.* FROM phones p, locations l, schools s
WHERE l.id = #{id} AND s.location_id = l.id AND p.school_id =
s.id”)
end

In which case you could use @some_location.get_phones

going a bit further than that it might be possible to use something like

@phone_numbers = Location.find( :all ).collect { |loc|
loc.get_phones}
@phone_numbers.flatten!

I haven’t tested andy of this tho… Hope it works :slight_smile: