This approach doesn't seem to be working for me.
I've set up the models as described above.
class Player < ActiveRecord::Base
has_many :outgoing_hits, :class_name => 'Hit', :foreign_key =>
'player_id'
has_many :incoming_hits, :class_name => 'Hit', :foreign_key =>
'hit_player_id'
has_many :hittees, :through => :outgoing_hits
has_many :hitters, :through => :incoming_hits
end
class Tag < ActiveRecord::Base
belongs_to :hitter, :class_name => 'Player'
belongs_to :hittee, :class_name => 'Player'
end
For player foo, I'm trying to list all the name of all players hit.
<ul>
<% @player.outgoing_hits.each do |hit| %>
<li><%=hit.hittee.screen_name%></li>
<%end%>
</ul>
But, "hittee" is null, although I can access other properties of the
hit.
You have a nil object when you didn't expect it!
The error occurred while evaluating nil.screen_name
Here's the key columns of the 2 tables involved:
Player{
id:integer
screen_name:varchar
}
Hit{
id:integer
player_id:integer
hit_player_id:integer
}
On Mar 28, 12:06 pm, Brad A <[email protected]> wrote:
> Thanks very much, I will give that a try. Yes I did have the column
> for player_id as "id", I mis-typed that, but its a good reminder,
> appreciated.
>
> -Brad
>
> On Mar 28, 11:13 am, Matt Jones <[email protected]> wrote:
>
> > A quick note first - Player most likely shouldn't have a player_id
> > column - the Rails convention is to simply call it id.
>
> > What you're looking for are some of the options to has_many:
>
> > class Player < ActiveRecord::Base
> > has_many :outgoing_hits, :class_name => 'Hit', :foreign_key =>
> > 'hitter_id'
> > has_many :incoming_hits, :class_name => 'Hit', :foreign_key =>
> > 'hittee_id'
>
> > has_many :hittees, :through => :outgoing_hits
> > has_many :hitters, :through => :incoming_hits
> > end
>
> > class Hit < ActiveRecord::Base
> > belongs_to :hitter, :class_name => 'Player'
> > belongs_to :hittee, :class_name => 'Player'
> > end
>
> > Given a Player object, this is what you can do:
>
> > player.outgoing_hits # => list of hits by the player
> > player.incoming_hits # => list of hits to the player
> > player.hittees # => list of all players hit by this player
> > player.hitters # => list of all players hitting this player
>
> > You can switch the names around, but that's the idea.
>
> > --Matt Jones
>
> > On Mar 27, 9:06 pm, Brad A <[email protected]> wrote:
>
> > > Consider 2 tables:
> > > Player-> column player_id
> > > and
> > > Hit-> columns player_id, hit_player_id
>
> > > I want one model for Player and one model for a Hit.
> > > Any player has many hits against another player.
> > > So from a Player I want to be able to get all the Hits, and from the
> > > Hit get the hit Player.
> > > On the other hand, from a Player I want to retrieve all Hits against
> > > that player (were player_id = hits.hit_player_id)
> > > and the player_id from that hit.
>
>
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