CODEWITHSUNDEEP
ruby-on-railsactiverecord
zakaria
zakaria

Reputation: 426

Ruby on rails active record: update a field by another field in the same record using update_all

How can I use update_all for the following purpose:

UPDATE  table_name set field1=field2 * 2 where id = 1

Upvotes: 2

Views: 732

Answers (2)

Santhosh
Santhosh

Reputation: 29094

In Rails4, you can do

Model.where(id: 1).update_all("field = field2 * 2")

In Previous versions of Rails, you can pass condition to update_all, like this

Model.update_all("field = field2 * 2", {:id => 1})

NOTE:

update_all does not trigger Active Record callbacks or validations

Upvotes: 5

Trevor
Trevor

Reputation: 43

I'm not 100% clear on your intention, but if you're just trying to do a 1 time update of all records that mach id = 1 running this in your console should work. 

Model.where("id = 1").each { |n|  (n.field1 = n.field2*2)}

Upvotes: 0

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