robo wrote:
> ok, I've got a model called Location, the idea being that i have a
> bunch of locations aligned to a grid. Each location has a pointer to
> it's neighbors, like so
>
> create_table "locations", :force => true do |t|
> t.string "name"
> t.text "description"
> t.integer "north"
> t.integer "northeast"
> t.integer "east"
> t.integer "southeast"
> t.integer "south"
> t.integer "southwest"
> t.integer "west"
> t.integer "northwest"
> t.integer "x"
> t.integer "y"
> t.datetime "created_at"
> t.datetime "updated_at"
> t.integer "map_id"
> end
>
> whereas all the directions (north, south, east, etc) should all be
> references to other locations.
>
> I know this is probably an easy question, but what kind of
> relationship is this, and how would I set it up in my model? like
> this?
>
> has_one :location, :foreign_key => :north
> has_one :location, :foreign_key => :northeast
> has_one :location, :foreign_key => :east
> has_one :location, :foreign_key => :southeast
> has_one :location, :foreign_key => :south
> has_one :location, :foreign_key => :southwest
> has_one :location, :foreign_key => :west
> has_one :location, :foreign_key => :northwest
I think I would avoid this. If the grid is regular, then you should
probably just store the X and Y coordinates in the model, then do
something like
class Location < AR::B
def northeast
@northeast ||= Location.find_by_x_and_y(x + 1, y + 1)
end
end
Best,
--
Marnen Laibow-Koser
http://www.marnen.org
[email protected]
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