Rails conditional migrations – ensure column does not exist

If you’re running into a rails migration exception, such as:

column “x” of relation “y” already exists

Then you can conditionally run the associated migration in the following way:

YourModel.reset_column_information
unless YourModel.column_names.include?("the_column")
  add_column(:your_models, :the_column, :boolean, :default=>true)
end

 
Of course, it is probably best to address the underlying workflow issues that caused this issue to occur in the first place. However, if you just want to move along to get along – the above is a great solution.