ActiveRecord select except columns

Question

Is there a way I can specify to select ALL columns in ActiveRecord except just a few. For example, for a User, I don\'t want to select their password hash or their email. Is

Answer 1

In some cases, particularly when you're considering a default_scope to exclude certain columns, I would advise against this approach because of a known issue with Rails about count breaking after a select clause. This can lead to surprising downstream errors.

In such a case, consider instead breaking your record into two tables, one with the essential data, the other one with the data you only need from time-to-time, then use associations to access the extra data.

Answer 2

write a scope like

def select_without columns
  select(column_names - columns.map(&:to_s))
end

Answer 3

Another really usefull way it's with a scope inside the model in case you need to avoid a column constantly.

In my case I save images into blob fields so I want to avoid those to be loaded everytime and in a easy way:

scope :select_exclude_image, ->  { select( Movie.attribute_names - ['image'] ) }

Then to avoid the image in the selection you can do something like that:

Movie.select_exclude_image.first

or

Movie.select_exclude_image.all

I hope it will help!

Answer 4

Something like this?

exclude_columns = ['password', 'email']
columns = User.attribute_names.delete_if(|x| exclude_columns.include?(x))

User.select(columns)

EDIT

I forgot that we can do Array1 - Array2

A best answer:

exclude_columns = ['password', 'email']
columns = User.attribute_names - exclude_columns

User.select(columns)