Rails add one to increment SQL value

Question

I am trying to add one to the already incremented field in the DB, but I am getting the following error: NoMethodError (undefined method+' for false:FalseClass):`

Code:

med = Media.find(params[:media_id])
med.update_attributes({:screener_viewed => med.screener_viewed + 1})

I am just wanting to add 1 to the current value of screener_viewed, but can't get it to work.

Working Code:

Media.increment_counter(:screener_viewed, params[:media_id])

bowsersenior · Accepted Answer · 2010-12-28 19:47:00Z

16

Use increment!:

med.increment!(:screener_viewed)

Make sure that screener_viewed is of type integer in your db.

answered Dec 28, 2010 at 19:47

bowsersenior

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2 Comments

dennismonsewicz Over a year ago

I actually just found this after refining my Google search! I am still new to Rails and I have no idea where it has been ALL my life, but I am definitely loving every minute of it! Thanks for the help!

bowsersenior Over a year ago

Glad this helped. Rails is definitely an eye-opener. I would advise you to also learn more about ruby itself. The awesomeness of Rails is in large part due to the "ruby way".

ryeguy · Accepted Answer · 2010-12-28 19:46:50Z

0

Examine the error message carefully. It says there is no addition method defined for the FalseClass, which means that screener_viewed contains a boolean value of false. Did you expect it to contain an integer, or are you trying to flip the value to true?

answered Dec 28, 2010 at 19:46

ryeguy

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Comments

A. Wilson · Accepted Answer · 2010-12-28 19:47:04Z

0

Could you provide the migration definition for the Media model? It looks like you've defined it as a Boolean, which does not support the + operator:

irb(main):002:0> false + 1
NoMethodError: undefined method `+' for false:FalseClass
        from (irb):2

answered Dec 28, 2010 at 19:47

A. Wilson

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Comments

user1094125 · Accepted Answer · 2014-09-18 20:31:08Z

0

Careful about using increment! I does not support concurrent request.

http://apidock.com/rails/ActiveRecord/Base/increment!

answered Sep 18, 2014 at 20:31

user1094125

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