Best way to filter a collection?

What is the best way to filter a collection of objects pulled from a
database before display? I can think of 3 and have run into problems
with each:

  1. Using SQL :joins and :conditions on Model.find. Problems: SQL is
    ugly and the attributes coming back on my objects are being overwritten
    (the ids that I need to pass to edit and delete actions are coming back
    as the ids of the last table joined, not the ids of the objects I’m
    requesting).

  2. Use Model.find(:all) then iterate through the collection (for
    @object in @objects) to remove the ones that don’t meet my criteria.
    Problem: I use @objects.delete(@object) to remove the unwanted objects
    from the collection, but it seems that (for @object in @objects) has
    some kind of internal counter and deleting an object from the
    collection shortens the collection by 1 so that the next iteration
    through @objects ends up skipping an object–in other words, if I were
    trying to delete all the objects, only every OTHER object would be
    deleted.

  3. Use Model.find(:all) then filter each object in the view. Problem:
    This logic shouldn’t be in the view, though at this point it’s the only
    way I know I can get it to work.

Any help is appreciated,
Isaac

isaac wrote:

  1. Use Model.find(:all) then iterate through the collection (for
    This logic shouldn’t be in the view, though at this point it’s the only
    way I know I can get it to work.

Any help is appreciated,
Isaac

The easiest way sort of depends on what you are doing, so an example
would be helpful.
In general #1 is your best approach. Just don’t retrieve records you
don’t need.

#2 won’t scale. If you have more than a few objects in your table, you
end up creating them all, which chews up memory and slows down the
server.

#3 has the same problem in addition to doing business logic in a
view…

In general, something like…

Model.find(:all, :conditions=>[“user = ?”, user_id])
or
model.users
(if you have your associations set up right)

will be your best bets.

_Kevin

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