uh oh, foreign key reference checking in MySQL, I can't believe it man 
you could try the before_destroy hook in certification, to delete the associated object:
class Certification before_destroy { |certification| certification.bio.destroy } Jens
I just re-read your mail - the above won't work either. Seems your foreign key constraint is the other way around - it says certification depends on bio, so you should say that in Rails, too, i.e., place the :dependent setting at the other end of the relationship.
That's why one should just place the model logic just into *one* place...
Jens
Dmitry,
Just a thought 'convention over configuration'....
Can you not just do a straight forward rails relationship using migrations?
class AddTables < ActiveRecord::Migration def self.up create_table :certifications, :force => true do |t| t.column :name, :string t.column :created_on, :date t.column etc... end
create_table :bios, :force => true do |t| t.column :certification_id, :integer t.column :name, :string t.column :created_on, :date t.column etc... end end
def self.down drop_table :certifications drop_table :bios end end
Then in your models you should only need;
class Certification < ActiveRecord::Base has_one :bio, :dependent => :destroy
class Bio < ActiveRecord::Base belongs_to :certification
And let rails take care of the rest?
Hrm.. can't get it working
what d u mean "place the :dependent setting at the other end of the relationship"?
I was confused by your naming of columns and the resulting mysql error.
My classes look like following:
class Certification < ActiveRecord::Base # before_destroy { |certification| certification.bio.destroy } has_one :bio, :class_name => "Bio", :foreign_key => "_key", :dependent => :destroy
class Bio < ActiveRecord::Base belongs_to :certification, :class_name => "Certification", :foreign_key => "_key"
what do your tables look like ? From these classes, you should have a '_key' column in the 'bio' table, referencing 'certification._key'. where in certification it's the primary key, and in bio it's a foreign key pointing to the certification this bio belongs to.
But from this message:
> Mysql::Error: #23000Cannot delete or update a parent row: a foreign > key
> constraint fails (`project/certification`, CONSTRAINT
> `FKD99554BA1D0B0B41` FOREIGN KEY (`_key`) REFERENCES `bio` > (`_key`)):
> DELETE FROM bio
> WHERE _key = 2
it looks as if there's a '_key' column in the certification table referencing the 'bio' row that should get deleted. Is it possible you specified the constraint in the opposite direction as intended ?
on a sidenote, that column naming doesn't make sorting this out any easier ...
Jens