ActiveRecord select except columns

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 this possible or do I have to manually hardcode all columns?

Thanks

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)

Just to add an option for people who want to exclude certain columns in every query by default can use the Rails 5 feature `ignored_columns`, which as the name suggests leaves those out.

The code is quite straightforward:

class User < ApplicationRecord
self.ignored_columns = %w[password email]
end

Please note that the [ignore_columns documentation][1] states that `You will get an error if accessing that attribute directly, so ensure all usages of the column are removed` so it may only work for cases where the columns are never required to be used.

[1]:

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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!

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][1] 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.


[1]:

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write a scope like

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