CODEWITHSUNDEEP
arrayspostgresqlruby-on-rails-4rails-activerecord
user3325749
user3325749

Reputation: 199

In Rails, how to add an element to an array type attribute for all records?

DB is PostgreSQL. How do you append a value for all records to a column that has an array data type?

For example: 

# migration_file.rb

def change
  add_column :users, :tags, :string, array: true, default: []
end

How do I append the same value to the tags attributes to all User records? I want to do something like:

User.update_all(tags << "some_tag")

Upvotes: 2

Views: 3570

Answers (1)

mu is too short
mu is too short

Reputation: 434615

You can pass an SQL snippet to update_all so you can use all the usual PostgreSQL array operators. For example:

User.update_all(['tags = tags || ?::text', 'some_tag'])

or without the || ambiguity (and corresponding cast):

User.update_all(['tags = array_append(tags, ?)', 'some_tag'])
User.update_all(['tags = tags || array[?]', 'some_tag'])

Note that you'd be passing update_all an array in this case, you need to do that to convince AR that you want 'some_tag' to fill in the placeholder rather than be the WHERE clause.

Upvotes: 5

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