delete_all vs destroy_all?

Solution 1:

You are right. If you want to delete the User and all associated objects -> destroy_all However, if you just want to delete the User without suppressing all associated objects -> delete_all

According to this post : Rails :dependent => :destroy VS :dependent => :delete_all

• destroy / destroy_all: The associated objects are destroyed alongside this object by calling their destroy method
• delete / delete_all: All associated objects are destroyed immediately without calling their :destroy method

Solution 2:

delete_all is a single SQL DELETE statement and nothing more. destroy_all calls destroy() on all matching results of :conditions (if you have one) which could be at least NUM_OF_RESULTS SQL statements.

If you have to do something drastic such as destroy_all() on large dataset, I would probably not do it from the app and handle it manually with care. If the dataset is small enough, you wouldn't hurt as much.