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Using ar-extensions' import: synchronise doesn't work

I am using AR-Extensions to import a large number of objects to db, but synching them back from DB just isn't working.

MY code:

posts = [Post.new(:name=>"kuku1"), Post.new(:name=>"kuku2"), ...]
Post.import posts, :synchronize=>posts

posts are submitted to db, and each one is allocated with primary key (id) automatically. But when afterwards checking the objects in posts array, I see that they don't have id field, and new_record flag is still true. I also tried adding :reload=>true, but that doesn't help as well.

Any idea why synch doesn't work?

Solution

  • This is not possible right now with new records. As of ar-extensions 0.9.3 this will not work when synchronizing new records as synchronizing expects the records you're sync'ing to already exist. It uses the primary key under the covers to determine what to load (but with new records the primary key is nil). This limitation* also exists in activerecord-import 0.2.5. If you can synchronize on other conditions I'd be happy to release a new gem allowing conditions to be passed in. For Rails 3.x you need to use activerecord-import though (it replaces ar-extensions). Please create ticket/issue on github: https://github.com/zdennis/activerecord-import/issues

    For Rails 2.x you still want to use ar-extensions, and I'd likely backport the activerecord-import update and push out a new gem as well. If you'd like this functionality here please create a ticket/issue on github: https://github.com/zdennis/ar-extensions/

    Patches are welcome as well.

    *The limitation here is a database constraint, as its impossible to get the ids of all newly created records after a single insert/import without doing something strange like table locking, which I don't think is a good solution to that problem. If anyone has ideas I'm all ears.

    UPDATE

    activerecord-import 0.2.6 and ar-extensions 0.9.4 have been released and includes support for specifying the fields you want to synchronize on. Those fields should be unique. See http://www.continuousthinking.com/2011/4/6/activerecord-import-0-2-6-and-ar-extensions-0-9-4