CODEWITHSUNDEEP
sqlruby-on-railsactiverecord
Craig Walker
Craig Walker

Reputation: 51797

Mass delete has_many associated rows in Rails

I have a model Foo and a model Bar, both of which has_many :bar_foos (and then has_many each other :through => :bar_foos). It's a simple many:many relationship between Foo and Bar, through a BarsFoo model.

I want to delete several rows in the bar_foos table. Specifically, I want to delete any bar_foo record that relates to any of a given set of Foos and any of a given set of Bars. For performance, I'd like to issue a single database call to do this.

The corresponding SQL statement would be:

DELETE FROM bar_foos WHERE bar_id IN ( ?, ?, ? ) AND foo_id in ( ?, ?, ? )

...while replacing the ?s with the appropriate IDs.

How do I perform this using Rails 2.3.x?

Ideally, I'd to not write the actual SQL myself, but make ActiveRecord method calls instead. However, I doubt this exists.

Barring that, I'll craft the SQL statement myself, but:

Upvotes: 1

Views: 1197

Answers (2)

Salil
Salil

Reputation: 47542

I think it's not possible using assosciation you have to write it your own (Use destroy_all)

BarFoo.destroy_all(["bar_id IN (?) AND foo_id in (?)", bar_id_array, foo_id_array])

Upvotes: 4

hwrd
hwrd

Reputation: 2180

You can do this...

has_many :bar_foos, :dependent => destroy

And that will destroy all the bar_foos that belong to the object that was just destroyed.

Upvotes: 0

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