Rails - Apr 2006 - Does ActiveRecord have support for "Boolean" columns?

Hey all --

I''ve been using enumerable char(1)''s with
''y'' and ''n'' values for my
Boolean columns in Rails, but it strikes me there should be a better
way.

How do you setup columns that represent true/false-ness in your
schemas on Rails?

Wondering what kind of standard approaches there are other than me
writing something like

class MyEntity < ActiveRecord::Base
  def active
     return false unless active==''y''
     true
  end
end

-- Brendan Baldwin (dot com)

> I''ve been using enumerable char(1)''s with
''y'' and ''n'' values for my
> Boolean columns in Rails, but it strikes me there should be a better
> way.
Just sharing, cuz I haven''t found a better way than yours -- I use 
tinyints, set after my migration has run, of course...

-- 
Posted via http://www.ruby-forum.com/.

If you use migrations to create your database, you can specify boolean
columns:

class CreateUsers < ActiveRecord::Migration
  def self.up
    create_table :users do |table|
      table.column :username, :string, :limit => 32, :null => false
      table.column :active, :boolean
    end
  end

  def self.down
    drop_table :users
  end
end

using MySQL for the DB, it creates a TINYINT(1) column, in which is stores 0
or 1.  ActiveRecord then treats it as a boolean.

On 4/4/06, Brendan Baldwin <brendan.baldwin@gmail.com>
wrote:
>
> Hey all --
>
> I''ve been using enumerable char(1)''s with
''y'' and ''n'' values for my
> Boolean columns in Rails, but it strikes me there should be a better
> way.
>
> How do you setup columns that represent true/false-ness in your
> schemas on Rails?
>
> Wondering what kind of standard approaches there are other than me
> writing something like
>
> class MyEntity < ActiveRecord::Base
>   def active
>      return false unless active==''y''
>      true
>   end
> end
>
> -- Brendan Baldwin (dot com)
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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> using MySQL for the DB, it creates a TINYINT(1) column, in which is 
> stores 0
> or 1.  ActiveRecord then treats it as a boolean.
Well, how ace is that?
Excuse me -- I have some migrations editing to do...
Cheers, man!

-- 
Posted via http://www.ruby-forum.com/.

Rails treats an integer field with 0 and 1 as a boolean. The 
checkbox_field helpers know what to do with 0 and 1 values, and scaffold 
generators create pulldowns for those fields with "True" and
"False" on
the labels and 0 and 1 as the return values.

If you use migrations to maintain your database schema, a command like

    add_column :salespeople, :has_been_trained, :boolean, :default => 
false

will create the appropriate field type for you. On MySQL this generates 
a tinyint(1) in the salespeople table, with a default of 0.

Brendan Baldwin wrote:
> Hey all --
> 
> I''ve been using enumerable char(1)''s with
''y'' and ''n'' values for my
> Boolean columns in Rails, but it strikes me there should be a better
> way.
> 
> How do you setup columns that represent true/false-ness in your
> schemas on Rails?
> 
> Wondering what kind of standard approaches there are other than me
> writing something like
> 
> class MyEntity < ActiveRecord::Base
>   def active
>      return false unless active==''y''
>      true
>   end
> end
> 
> -- Brendan Baldwin (dot com)

-- 
Posted via http://www.ruby-forum.com/.

I generated my models from postgresql tables with booleans in them.  They
seem to work fine without any extra effort.
>
>
>
> --
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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Each of the database adapters is responsible for determining how to  
handle a boolean column in a way that makes sense for their specific  
backend.  In the case of PostgreSQL and OpenBase this is trivial,  
since these database backends have a boolean type column built-in.   
For MySQL - as has been pointed out - booleans are usually handled as  
tinyint.  The MySQL adapter therefore will default to handle tinyint  
columns as booleans.  However, this behavior can be changed by  
setting MysqlAdapter.emulate_booleans = false.

If you define your schema within rails and give the column a type  
of :boolean, then the adapter you are using will create a column of  
whatever type makes sense for that database, thus achieving (at least  
to this extent) database agnosticism.  Beautiful.  Sorta brings a  
tear to your eye, doesn''t it?

-Derrick Spell


On Apr 4, 2006, at 4:30 PM, Brendan Baldwin wrote:
> Hey all --
>
> I''ve been using enumerable char(1)''s with
''y'' and ''n'' values for my
> Boolean columns in Rails, but it strikes me there should be a better
> way.
>
> How do you setup columns that represent true/false-ness in your
> schemas on Rails?
>
> Wondering what kind of standard approaches there are other than me
> writing something like
>
> class MyEntity < ActiveRecord::Base
>   def active
>      return false unless active==''y''
>      true
>   end
> end
>
> -- Brendan Baldwin (dot com)
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

Thats great news about MySQL and TinyInt :-)  I didn''t realize that
one.

Thanks for the replies everyone!  I think I''m going to start exploring
Migrations now.

--Brendan

On 4/5/06, Derrick Spell <derrickspell@cdmplus.com>
wrote:
> Each of the database adapters is responsible for determining how to
> handle a boolean column in a way that makes sense for their specific
> backend.  In the case of PostgreSQL and OpenBase this is trivial,
> since these database backends have a boolean type column built-in.
> For MySQL - as has been pointed out - booleans are usually handled as
> tinyint.  The MySQL adapter therefore will default to handle tinyint
> columns as booleans.  However, this behavior can be changed by
> setting MysqlAdapter.emulate_booleans = false.
>
> If you define your schema within rails and give the column a type
> of :boolean, then the adapter you are using will create a column of
> whatever type makes sense for that database, thus achieving (at least
> to this extent) database agnosticism.  Beautiful.  Sorta brings a
> tear to your eye, doesn''t it?
>
> -Derrick Spell
>
>
> On Apr 4, 2006, at 4:30 PM, Brendan Baldwin wrote:
>
> > Hey all --
> >
> > I''ve been using enumerable char(1)''s with
''y'' and ''n'' values for my
> > Boolean columns in Rails, but it strikes me there should be a better
> > way.
> >
> > How do you setup columns that represent true/false-ness in your
> > schemas on Rails?
> >
> > Wondering what kind of standard approaches there are other than me
> > writing something like
> >
> > class MyEntity < ActiveRecord::Base
> >   def active
> >      return false unless active==''y''
> >      true
> >   end
> > end
> >
> > -- Brendan Baldwin (dot com)
> > _______________________________________________
> > Rails mailing list
> > Rails@lists.rubyonrails.org
> > http://lists.rubyonrails.org/mailman/listinfo/rails
> >
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

I don''t think this was mentioned yet. You can place a question mark  
after the getter method to inform ActiveRecord that you expect the  
attribute to be a boolean. For example:

entity = MyEntity.find(:first)
if entity.active?
   # do something
end

This is good for a couple reasons:

1. It follows the ruby standard of placing a question mark after a  
method which returns a boolean.
2. It converts the column value into a boolean. Example: ''0'',
''f'',
''false'', and '''' (empty string) all return
false. Everything else
returns true. Unfortunately, it doesn''t recognize "n" as
false.

Hope that helps.

Ryan

On Apr 6, 2006, at 3:25 PM, Brendan Baldwin wrote:
> Thats great news about MySQL and TinyInt :-)  I didn''t realize
that
> one.
>
> Thanks for the replies everyone!  I think I''m going to start
exploring
> Migrations now.
>
> --Brendan
>
> On 4/5/06, Derrick Spell <derrickspell@cdmplus.com> wrote:
>> Each of the database adapters is responsible for determining how to
>> handle a boolean column in a way that makes sense for their specific
>> backend.  In the case of PostgreSQL and OpenBase this is trivial,
>> since these database backends have a boolean type column built-in.
>> For MySQL - as has been pointed out - booleans are usually handled as
>> tinyint.  The MySQL adapter therefore will default to handle tinyint
>> columns as booleans.  However, this behavior can be changed by
>> setting MysqlAdapter.emulate_booleans = false.
>>
>> If you define your schema within rails and give the column a type
>> of :boolean, then the adapter you are using will create a column of
>> whatever type makes sense for that database, thus achieving (at least
>> to this extent) database agnosticism.  Beautiful.  Sorta brings a
>> tear to your eye, doesn''t it?
>>
>> -Derrick Spell
>>
>>
>> On Apr 4, 2006, at 4:30 PM, Brendan Baldwin wrote:
>>
>>> Hey all --
>>>
>>> I''ve been using enumerable char(1)''s with
''y'' and ''n'' values for my
>>> Boolean columns in Rails, but it strikes me there should be a
better
>>> way.
>>>
>>> How do you setup columns that represent true/false-ness in your
>>> schemas on Rails?
>>>
>>> Wondering what kind of standard approaches there are other than me
>>> writing something like
>>>
>>> class MyEntity < ActiveRecord::Base
>>>   def active
>>>      return false unless active==''y''
>>>      true
>>>   end
>>> end
>>>
>>> -- Brendan Baldwin (dot com)
>>> _______________________________________________
>>> Rails mailing list
>>> Rails@lists.rubyonrails.org
>>> http://lists.rubyonrails.org/mailman/listinfo/rails
>>>
>>
>> _______________________________________________
>> Rails mailing list
>> Rails@lists.rubyonrails.org
>> http://lists.rubyonrails.org/mailman/listinfo/rails
>>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails

On Apr 7, 2006, at 1:29, Ryan Bates wrote:
> I don''t think this was mentioned yet. You can place a question
mark
> after the getter method to inform ActiveRecord that you expect the  
> attribute to be a boolean. For example:
>
> entity = MyEntity.find(:first)
> if entity.active?
>   # do something
> end
In addition you can use booleans in find_bys:

    entity = MyEntity.find_all_by_active(true) # no SQL here

Since that''s a little tricky I try to avoid hard-coding any boolean- 
like literal as one would do with :conditions.

-- fxn