How to Use Helpermethod

Question

I created an helper in my application_helper:

 def birthday(geburt)
   f = Date.today
   a = f.year - geburt.year
   a = a - 1 if (
     geburt.month >  f.month or 
    (geburt.month >= f.month and geburt.day > f.day)
    )
    a
 end

Now i try tu use this helper in an model:

 patients = patients.where("birthday(geburtsdatum) >= ?", minimum) if minimum.present?

But how you can see in the error i somehow dont use my helper right. "geburtsdatum" is an colomn in my patients model. Thanks Error:

 SQLite3::SQLException: no such function: birthday: SELECT "patients".* FROM "patients"  WHERE (birthday(geburtsdatum) >= 15) ORDER BY vorname

My new code:

def find_patients
 patients = Patient.order(:vorname)
 patients = patients.where("nachname like ?", "%#{keyword}%") if keyword.present?
 patients = patients.where("#{geburtsdatum.get_birthday} >= ?", minimum) if   minimum.present?
 patients
end

My new error:

undefined local variable or method `geburtsdatum' for #<Search:0x4ee51b8>

Billy Chan · Accepted Answer · 2013-09-14T13:25:02.287

1

Got it, then the method is for Date objects.

Including helper is doable as you mentioned in that reference but not a good practice. You can do it for a quick fix, nothing wrong.

Just for your reference, in my opinion a better approach is to extend Date class in your app to add such method and then you can call it on a Date object like some_date.process_birthday.

You can add such file in /app, or /initializers, or /lib(better but need manual require).

Then

class Date
  def get_birthday
    f = Date.today
    a = f.year - self.year
    if (self.month >  f.month) || (self.month >= f.month && self.day > f.day)
      a = a - 1
    end 
    a
  end
end

edited Sep 14 '13 at 13:25

answered Sep 14 '13 at 12:58

Billy Chan

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Geburtsdatum is german, in englisch = Birthday! But can you explain me your recommendation further? Thanks – John Smith Sep 14 '13 at 13:00
I dont know but here it says http://stackoverflow.com/questions/489641/using-helpers-in-model-how-do-i-include-helper-dependencies – John Smith Sep 14 '13 at 13:01
thanks, i put your code into initializers get_birthday.rb. Then in the model patients.where("geburtsdatum.get_birthday >= ?", m..... But somehow it says no such column: geburtsdatum.get_birthday !!!! How do i have to write it? Thanks – John Smith Sep 14 '13 at 13:31
1

Firstly is the geburtsdatum really exist as a date object? If it is, you need interpolation the ruby code if they are in a string "#{geb.get_birthday} >= ..." – Billy Chan Sep 14 '13 at 13:57
Yes its defined as date! I have to say we are nearly the goal! I updated the question! There you can see my new code and error! – John Smith Sep 14 '13 at 14:05
1

If it's undefined, you need to define it. Verify if that variable or method does exist. – Billy Chan Sep 14 '13 at 14:08
In my patients model i have geburtsdatum:date – John Smith Sep 14 '13 at 14:10
I think the problem is that rails does not know that geburtsdatum belongs to an patient – John Smith Sep 14 '13 at 14:12
If this is a method, it should be class method `def self.geb` – Billy Chan Sep 14 '13 at 14:14
sorry but where should i put the self? – John Smith Sep 14 '13 at 14:17

How to Use Helpermethod

1 Answers1