Spot the error (I can't, I'm new)

Rails
1

I have a form that I want to use to update multiple
objects. In the controller,
@grades = Grade.find(params[:grade].keys)
@grades.each_with_index do |grade, i|
grade.update_attribute(params[:grade][i])
end
all_valid = @grades.inject(true) {|memo, c|
c.valid? && memo }
this doesn’t update the attributes as I would expect.
(I would just use
Grade.update(params[:grade].keys,params[:grade].values)
but I can’t figure out how to validate the data using
that method. Could someone please explain what I’m
doing wrong here?

Thanks,
Brian Gates

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2

For one thing, remember that update_attribute is for updating a single
attribute. It looks like you’re updating multiple attributes per grade
in your each loop, so you probably want to use update_attributes
instead, no?

B Gates wrote:

I have a form that I want to use to update multiple
objects. In the controller,
@grades = Grade.find(params[:grade].keys)
@grades.each_with_index do |grade, i|
grade.update_attribute(params[:grade][i])
end
all_valid = @grades.inject(true) {|memo, c|
c.valid? && memo }
this doesn’t update the attributes as I would expect.
(I would just use
Grade.update(params[:grade].keys,params[:grade].values)
but I can’t figure out how to validate the data using
that method. Could someone please explain what I’m
doing wrong here?

Thanks,
Brian Gates

Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com

3

update attribute takes 2 parameters: the name of the attribute and its
new value, you are only giving it the value, and it doesnt know what
field you are talking about.

Try:
grade.update_attribute(:letter_grade, params[:grade][i])

Or with a bit of refactoring:
@grades = []
params[:grade].each_pair do |key, value|
grade = Grade.find(key)
grade.update_attribute(:letter_grade, value)
@grades << grade
end
all_valid = @grades.inject(true) do |memo, c|
c.valid? && memo
}

This wau you don;t have to use “params[:grade][i]” which is standard
practice in other languages, but in ruby it’s usually quite unnesesary.

-Alex

B Gates wrote:

I have a form that I want to use to update multiple
objects. In the controller,
@grades = Grade.find(params[:grade].keys)
@grades.each_with_index do |grade, i|
grade.update_attribute(params[:grade][i])
end
all_valid = @grades.inject(true) {|memo, c|
c.valid? && memo }
this doesn’t update the attributes as I would expect.
(I would just use
Grade.update(params[:grade].keys,params[:grade].values)
but I can’t figure out how to validate the data using
that method. Could someone please explain what I’m
doing wrong here?

Thanks,
Brian Gates

Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com