tinyint(1) and boolean

rubyonrails-talk
1

So i had a boolean attribute in my model which gets interpreted to tinyint(1) in mysql by rails migrations. Now tinyint(1) accepts a range in mysql and i want to change my boolean attribute to an attribute which can accept 3 values(0,1,2). I made the change to the view and when i post the form selecting the selecting the value '2', it still gets saved as a '0'. I checked the params when the post is done and the value of the form element was '0' even though i selected '2'(I am using a dropdown list here). So my question really is, how can i make rails to accept more values without changing the type to something other than tinyint(1)? And why this weirdness?

thanks in advance.

2

Mysql doesn't have an actual boolean type so rails usually uses tinyint (1) columns instead. There is a setting inside the mysql_adapter called emulate_booleans which you could try turning off but that would apply to all tables.

Fred

3

As others have pointed out, MySQL doesn't have a straight "boolean" field type, so the tinyint(1) hack is used instead.

You'll either need to turn off emulate_booleans (which may break other stuff) or just change the column type, as the MySQL adapter will detect the current type as :boolean and the AR-generated accessors will wind up casting values as booleans automatically...

Not to mention the potential for confusion - imagine you're another developer, looking at schema.rb. You see a field 'foo' declared as :boolean, and the interface stuffs '2' in there - what's it supposed to mean? FILE_NOT_FOUND? :slight_smile:

--Matt Jones

4

I second Matt's point about potential for confusion. A boolean val implies one of two values: true or false. What you're asking for -- 1 of 3 potential vals -- seems to rule out the use of a boolean to represent that val. So, I'd recommend using some other data type.

Jeff

5

Updating this old post, because there’s now a way to handle situations where you’ve got a tinyint(1) column that has non-0/1 values in it.

The relevant documentation is here: rails/attributes.rb at daffea59db118fce4247d335eabea026cc54d7bc · rails/rails · GitHub

Note that in 4.2.1 the entire module is #:nodoc:, but it has been made public in master.

To use it, you redeclare a column that would otherwise be misdetected. Example:

class SomeModel < ActiveRecord::Base

attribute :a_tinyint_1_column_that_isnt_a_boolean, Type::Integer.new

end

Passing an instance of ActiveRecord::Type::Integer means the column will not have the boolean typecasting behavior anymore.

–Matt Jones