HI,
I have a question about uniqueness scope.
I have a Scale model with this fields
group_id
name
min_val
max_val
category
for example the first record will have as
- min_val : 0
- max_val : 10
and the next values shouldn''t be in that range.
I discovered that I can do this....
validates :min_val, :uniqueness => { :scope => :group_id},
But I want to validate that the new min/max value is not in a already
saved record
Is there a rails way to do that?
Thanks
Javier Q.
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On Wed, Dec 14, 2011 at 12:06, JavierQQ <jquarites-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> I have a Scale model with this fields > group_id > name > min_val > max_val > category > > for example the first record will have as > - min_val : 0 > - max_val : 10 > > and the next values shouldn''t be in that range. > > I discovered that I can do this.... > > validates :min_val, :uniqueness => { :scope => :group_id}, > > But I want to validate that the new min/max value is not in a already > saved record > > Is there a rails way to do that?If I understand rightly, what you want to do is to divide the space up into non-overlapping ranges. Is that correct? If so, then you could use a validator function that checks the new record against all saved records to see if there is overlap. That would be rather inefficient, though, so if you''re adding new Scales frequently, it could slow down the system. If adding Scales is very rare, then remember the old maxim: all algorithms are fast, for sufficiently small values of N. ;-) Alternately, you could just forget about max and just record the min, with the implied max being just below the min of the next group when sorted by min. That would also ensure you have no holes, except below the lowest min. However, that could be less efficient in usage (finding the right range for a value) because you''d have to make sure that not only is it above this min, but there are no higher mins it''s below.... -Dave -- LOOKING FOR WORK! What: Ruby (on/off Rails), Python, other modern languages. Where: Northern Virginia, Washington DC (near Orange Line), and remote work. See: davearonson.com (main) * codosaur.us (code) * dare2xl.com (excellence). Specialization is for insects. (Heinlein) - Have Pun, Will Babble! (Aronson) -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
On Fri, Dec 16, 2011 at 10:22 AM, Dave Aronson < googlegroups2dave-BRiZGj7G2yRXqviUI+FSNg@public.gmane.org> wrote:> > If I understand rightly, what you want to do is to divide the space up > into non-overlapping ranges. Is that correct? If so, then you could > use a validator function that checks the new record against all saved > records to see if there is overlap. That would be rather inefficient, > though, so if you''re adding new Scales frequently, it could slow down > the system. If adding Scales is very rare, then remember the old > maxim: all algorithms are fast, for sufficiently small values of N. > ;-) > > Alternately, you could just forget about max and just record the min, > with the implied max being just below the min of the next group when > sorted by min. That would also ensure you have no holes, except below > the lowest min. However, that could be less efficient in usage > (finding the right range for a value) because you''d have to make sure > that not only is it above this min, but there are no higher mins it''s > below.... > > -Dave > >Yes I think is more a query problem than something of rails I''ve already made a validation that won''t let a user to save this : - min_v : 10 - max_v : 1 That validation was easy :) , but (for example) what if I have this -min_v : 0 -max_v :10 another -min_v : 21 -max_v : 30 and then someone wants to save this - min_v : 8 - max_v :25 I have to do some validation about it, I found this http://stackoverflow.com/questions/5028612/reservation-type-system-w-validation-rails-3-0 def uniqueness_of_date_range errors.add(:start_date, "not available") unless Room.where("? >start_date" AND ? <= end_date", start_date, start_date).count == 0 errors.add(:end_date, "not available") unless Room.where("? >start_date" AND ? <= end_date", end_date, end_date).count == 0 end but ... is there a better way? Thanks Javier -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
On Fri, Dec 16, 2011 at 10:36, Javier Quarite <jquarites-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:> I have to do some validation about it, I found this > http://stackoverflow.com/questions/5028612/reservation-type-system-w-validation-rails-3-0 > > def uniqueness_of_date_range > errors.add(:start_date, "not available") unless Room.where("? >> start_date" AND ? <= end_date", start_date, start_date).count == 0 > errors.add(:end_date, "not available") unless Room.where("? >= start_date" > AND ? <= end_date", end_date, end_date).count == 0 > end > > but ... is there a better way?Somewhat. That approach could add the same error twice. I''d probably do it as: errors.add(:start_date, "not available") unless (Room.where("? >= start_date AND ? <= end_date", start_date, start_date).count == 0 and Room.where("? >= start_date AND ? <= end_date", end_date, end_date).count == 0) (Basically, instead of "error unless x" and then "same error unless y", use "error unless x and y".) Also I tend not to use "unless" very much; I don''t think this particular usage is any clearer than using "if" and checking whether count > 0. But that''s just a matter of personal style. Other than that, yes, it''s pretty much what I was thinking. -Dave -- LOOKING FOR WORK! What: Ruby (on/off Rails), Python, other modern languages. Where: Northern Virginia, Washington DC (near Orange Line), and remote work. See: davearonson.com (main) * codosaur.us (code) * dare2xl.com (excellence). Specialization is for insects. (Heinlein) - Have Pun, Will Babble! (Aronson) -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org To unsubscribe from this group, send email to rubyonrails-talk+unsubscribe@googlegroups.com. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
I just didn''t follow that code... because I wasn''t sure enough
how would it
handle the data,
by that I mean... how does rails know wich one is the data that is going to
be validated and the data used for the validation,
I was searching and I guess the that a solution can be made with Proc.new
validates :minimun_value,
:uniqueness => {:scope=> [:group_id]},
:exclusion => { :in => Proc.new{|r|
[(r.minimun_value)..(r.maximun_value)]}}
(the model Scale belongs_to Group, and Group has_many scales)
but nothing happens. I choose Proc.new because (as far as I understood) it
let me go through the entire table, is that correct?
Javier Q.
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