(Rails 2.3.4)
Can’t quite figure out what I’m doing wrong but I’m seeing different
behavior for validates_uniqueness_of between two models that look more
ore less identical to me –
I have a model called Person:
class Person < ActiveRecord::Base
validates_uniqueness_of :first_name, :scope => :last_name
end
I also have a model called Setting (application settings object):
class Setting < ActiveRecord::Base
validates_uniqueness_of :setting, :scope => :category
{some class methods}
end
Here’s the schemas:
create_table “people”, :force => true do |t|
t.string “last_name”
t.string “first_name”
t.datetime “created_at”
t.datetime “updated_at”
end
create_table “settings”, :force => true do |t|
t.string “setting”
t.string “value”
t.float “num_value”
t.string “category”
t.string “tag”
t.datetime “created_at”
t.datetime “updated_at”
end
When I try to add a Person where two rows have the same first name, but
different last names, I’m able to save both records successfully.
However when I try to add a Setting where two rows have the same
‘setting’, but different ‘category’, I got an
ActiveRecord::RecordInvalid: Validation failed: Setting has already been
taken
Interstingly, the executed SQL in the log file when checking enforcement
of the constraint seems to be different for the two models, although so
far as I can see, the structure is similar in all the relevant
dimensions:
SELECT people.id FROM people WHERE (people.first_name = BINARY
‘jack’ AND people.last_name = ‘kramer’) LIMIT 1
whereas the check performed for dupes in setting is:
SELECT * FROM settings WHERE (settings.setting IN
(’settings.setting = BINARY ? AND settings.category =
?’,‘width’,‘frame’)) LIMIT 1
(Note that his returned “false” even though there is no Setting where
s.category = “frame”
What am I doing wrong? Why is genereated sql for People simply “where
a and b” with for Settings it is
where (a in (b and c))?
Thanks.