Hi there, I'm not a SQL expert and it the first time that I play with
sequel, so maybe I'm missing the point.
I wanted to test many_to_many association using a join table with
attributes.
There is my sample with comments.
require 'sequel'
#
LOGGER = Object.new()
def LOGGER.method_missing( name, args )
puts "[#{name}] #{args}"
end
DB = Sequel.sqlite('sql_test.db', :loggers => [LOGGER] )
#
Sequel::Model.plugin(:schema)
#
class T1 < Sequel::Model
set_schema do
primary_key :id, :auto_increment => true
text :a1
end
one_to_many :tjoin
many_to_many :t2s, :join_table=>:tjoins
end
#
class T2 < Sequel::Model
set_schema do
primary_key :id, :auto_increment => true
text :a2
end
one_to_many :tjoin
many_to_many :t1s, :join_table=>:tjoins
end
#
class Tjoin < Sequel::Model
set_schema do
foreign_key :t1_id, :table => :t1s, :null => false
foreign_key :t2_id, :table => :t2s, :null => false
text :ajoin #, :null => false I would love to be able to use
it *sigh*
primary_key [:t1_id,:t2_id]
end
many_to_one :t1
many_to_one :t2
end
#
T1.create_table!
T2.create_table!
Tjoin.create_table!
# why is there a (SELECT ... LIMIT 1) statement executed after each
INSERT, UPDATE, ETC
t1 = T1.create(:a1=>'A')
t2 = T2.create(:a2=>'B')
t1.add_t2 t2
# isn't there a better way to do that ??
Tjoin.where(:t1_id=>t1.id,:t2_id=>t2.id).first.update(:ajoin=>'JOIN')
#
class T1
# I'm not really happy with this one, but maybe that's the way ?
def my_add t2, attr
add_t2 t2
Tjoin.where(:t1_id=>self.id,:t2_id=>t2.id).first.update
(:ajoin=>attr)
end
end
t3 = T2.create(:a2=>'C')
t1.my_add t3, 'MY_ADD'
# isn't ther a way to produce something like this
puts DB[:tjoins,:t1s].select(:tjoins.*).where
(:tjoins__t1_id=>:t1s__id).and(:t1s__a1=>'A').sql
# using Sequel::Model ???
T1.where(:a1=>'A').first.tjoin_dataset.each do |set| puts set end
Any comment will be appreciated.
Thanks
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