I'm writing a migration script which has to, well, actually migrate
all data from table A to table B, but I need to access the application
logic in model A for each row migrated. I could do this:
MyModel.all.each do |instance|
# do stuff...
but as far as I know that would pre-instantiate all records in memory
beforehand, which could be *really bad* with the amount of records I'm
dealing with, and I only really need to work with a record at a time.
An alternative I'm currently using is:
execute("SELECT * FROM table_a").each_hash do |row|
instance = MyModel.new(row)
but I believe this is also sub-optimal (especially since some
attributes are attr_protected, therefore I'm having to take care of
those manually, and other reasons).
Is there any obvious/elegant way of doing this I'm missing?