I want to create a calculated field that multiply column1 and column2 on rails 3.
Like this :
totalpoint = column1 * column2
Where is I have to place the code? in the model? How do I write it?
How do I call it from my view?
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2 Answers
I think this is better placed on the model
attr_reader :totalpoint
def totalpoint
column1 * column2
end
Give some instance @m of your model, it can be accessed anywhere (in an action, in the view, etc..) as
@m.totalpoint
You can access this from within the model simply with
@totalpoint
Comments
In your controller create put the calculation in a instance variable (starts with @) in the action that is being called, eg index:
def index
@totalpoint = column1 * column2
end
In your view (index.html.erb) you can use the instance variable:
<div>
Total point = <%= @totalpoint %>
</div>
If you need to do this for multiple rows, you can use an array and use it in your view.