Rails - Aug 2007 - How do I assign default values to model attribute

I have a model with a attribute named "code". Every time i create an
instance I want the "code" to be initialized by making a call to
"generate_code" method. How do i initialize model attributes in rails
??

thanks for help.
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Jigar Gosar wrote:
> I have a model with a attribute named "code". Every time i create
an
> instance I want the "code" to be initialized by making a call to
> "generate_code" method. How do i initialize model attributes in
rails ??
> 
> thanks for help.
Add this line to your model class:
  before_create :generate_code

generate_code will be called when you ''save'' an new instance
just before
it is sent to the database.  There are a number of these methods, called 
CallBacks available.  You may what to look through a list of them and 
see if there isn''t one that might work better for your particular 
situation.
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I want a call back on object construction, not on save or on create. but 
for now i think before_create will work for me.

John Miller wrote:
> Jigar Gosar wrote:
>> I have a model with a attribute named "code". Every time i
create an
>> instance I want the "code" to be initialized by making a call
to
>> "generate_code" method. How do i initialize model attributes
in rails ??
>> 
>> thanks for help.
> 
> Add this line to your model class:
>   before_create :generate_code
> 
> generate_code will be called when you ''save'' an new
instance just before
> it is sent to the database.  There are a number of these methods, called 
> CallBacks available.  You may what to look through a list of them and 
> see if there isn''t one that might work better for your particular 
> situation.
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Jigar Gosar wrote:
> I want a call back on object construction, not on save or on create. but 
> for now i think before_create will work for me.
> 
> John Miller wrote:
>> Jigar Gosar wrote:
>>> I have a model with a attribute named "code". Every time
i create an
>>> instance I want the "code" to be initialized by making a
call to
>>> "generate_code" method. How do i initialize model
attributes in rails ??
>>> 
>>> thanks for help.
>> 
>> Add this line to your model class:
>>   before_create :generate_code
>> 
>> generate_code will be called when you ''save'' an new
instance just before
>> it is sent to the database.  There are a number of these methods,
called
>> CallBacks available.  You may what to look through a list of them and 
>> see if there isn''t one that might work better for your
particular
>> situation.
how about using

class Klass

def initialize(default_att1, att2, att3)
@default_att = default_att1
@att2 = att2
end

end

whenever you pass a .new method, initialize is called:

var = Klass.new(10, '''', ''value'')

var is now

var.default_att1 = 10
var.att2 = ''''
var.att3 = ''value''

helps?

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Sounds good, I try it. I hope it dosen''t conflict with the default
constructor of AR class.

Shai Rosenfeld wrote:
> class Klass
> 
> def initialize(default_att1, att2, att3)
> @default_att = default_att1
> @att2 = att2
> end
> 
> end
> 
> whenever you pass a .new method, initialize is called:
> 
> var = Klass.new(10, '''', ''value'')
> 
> var is now
> 
> var.default_att1 = 10
> var.att2 = ''''
> var.att3 = ''value''
> 
> helps?
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use the

super

special keyword; it inherits the parent''s class methods, so it takes
the
super method, and modifies it for your needs:

http://jamescrisp.blogspot.com/2006/09/rails-and-initialize-method.html
(in the link-example, you don''t need the "if" clause supplied
there)


Jigar Gosar wrote:
> Sounds good, I try it. I hope it dosen''t conflict with the default
> constructor of AR class.
> 
> Shai Rosenfeld wrote:
>> class Klass
>> 
>> def initialize(default_att1, att2, att3)
>> @default_att = default_att1
>> @att2 = att2
>> end
>> 
>> end
>> 
>> whenever you pass a .new method, initialize is called:
>> 
>> var = Klass.new(10, '''', ''value'')
>> 
>> var is now
>> 
>> var.default_att1 = 10
>> var.att2 = ''''
>> var.att3 = ''value''
>> 
>> helps?
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