Help with has_and_belongs_to_many

Ruby
1

class Trade < ActiveRecord::Base

 has_and_belongs_to_many :tags

class Tag < ActiveRecord::Base
set_table_name “tags”
has_and_belongs_to_many :trades

end

how to i add records to the table tags_trades using active rcord. i
dont have a model for tags_trades becaues the docs states that i
dont need one.

thanks in advance.

2

Junkone wrote:

class Trade < ActiveRecord::Base

 has_and_belongs_to_many :tags

class Tag < ActiveRecord::Base
set_table_name “tags”
has_and_belongs_to_many :trades

end

how to i add records to the table tags_trades using active rcord. i
dont have a model for tags_trades becaues the docs states that i
dont need one.

thanks in advance.

Well, first off, you forgot to end the Trade class. And you forgot to
give it a table name.

Once you’ve done that, and you’ve created your instance of the Trade
class (let’s call it trade, just to be simple…) and a bunch of Tag
classes with silly names:

trade.tags = [cheese, timeshare, lubricant]

3

On Dec 7, 2:55 am, Peter B. [email protected] wrote:

class (let’s call it trade, just to be simple…) and a bunch of Tag
classes with silly names:

trade.tags = [cheese, timeshare, lubricant]

Posted viahttp://www.ruby-forum.com/.- Hide quoted text -

  • Show quoted text -

i tried that but does not work.
i do have the table defined
CREATE TABLE tags_trades (
tag_id int(11) NOT NULL,
trade_id int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

i get error when assigning many to many relationship

a=Trade.find(1)
=> #<Trade:0x477f4bc @attributes={“tradestatus”=>“O”, “size”=>nil,
“mfe”=>nil, "
tradestrategy"=>nil, “symbol_alias”=>“PRGX”, “tradeinterval”=>“DAILY”,
“getpictu
res”=>nil, “tradename”=>nil, “id”=>“1”, “mae”=>nil,
“grossrevenue”=>nil, “tradec
omments”=>nil, “tradedirection”=>“Short”}>
z=Tag.find(1)
=> #<Tag:0x4779044 @attributes={“id”=>“1”, “description”=>“exampe1”}>
a.tags=z
NoMethodError: undefined method each' for #<Tag:0x4779044> from e:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/ active_recor d/base.rb:1863:in method_missing’
from e:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/
active_recor
d/associations/association_collection.rb:141:in replace' from e:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/ active_recor d/associations.rb:962:in tags=’
from (irb):37

4

On 12/7/07, Junkone [email protected] wrote:

=> #<Tag:0x4779044 @attributes={“id”=>“1”, “description”=>“exampe1”}>

a.tags=z
NoMethodError: undefined method `each’ for #Tag:0x4779044
from e:/ruby/lib/ruby/gems/1.8/gems/activerecord-1.15.5/lib/

You don’t replace a habtm relationship with an assignment, you add to it

a.tags << z

–
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/

5

On Dec 7, 9:45 am, Rick DeNatale [email protected] wrote:

omments"=>nil, “tradedirection”=>“Short”}>
–
Rick DeNatale

My blog on Rubyhttp://talklikeaduck.denhaven2.com/

thanks. how do you do the reverse. if i want to remove an existing
relationship.

6

On 12/7/07, Junkone [email protected] wrote:

On Dec 7, 9:45 am, Rick DeNatale [email protected] wrote:

You don’t replace a habtm relationship with an assignment, you add to it

a.tags << z

thanks. how do you do the reverse. if i want to remove an existing
relationship.

      a.tags.delete(z)

–
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/

7

On Dec 7, 12:05 pm, Rick DeNatale [email protected] wrote:

–
Rick DeNatale

My blog on Rubyhttp://talklikeaduck.denhaven2.com/

thanks a lot.