Forum: Ruby on Rails delete rows not updated

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8133ee52ca72188132b5c7d97dfb967f?d=identicon&s=25 Me (Guest)
on 2009-01-05 21:16
(Received via mailing list)
Is there an easy way to delete all rows not updated when done updating
a db?
8217faf2bfdfa7daf10135d41ddd421e?d=identicon&s=25 Jeff Cohen (jeff)
on 2009-01-05 21:29
(Received via mailing list)
On Jan 5, 2:15 pm, Me <chabg...@gmail.com> wrote:
> Is there an easy way to delete all rows not updated when done updating
> a db?

What in the world do you mean?

Hard to answer a question without any details or context to what
you're doing. :-)

Jeff
purpleworkshops.com
8133ee52ca72188132b5c7d97dfb967f?d=identicon&s=25 Me (Guest)
on 2009-01-05 21:32
(Received via mailing list)
I have a table of data that I update with a file.  I would like to
delete all data that does not get updated.
36aef9956c6082f69622dd67e8da376f?d=identicon&s=25 Joshua Abbott (joshnabbott)
on 2009-01-05 22:50
How are you checking to see if the row was updated or not? By the
updated_at timestamp, or something else?

I'm not sure if you're asking for help coming up with a way to determine
whether or not a row should be deleted, or just how to delete it.

The how to delete is simple enough, I guess. Just loop through the
records and call destroy on the object if it doesn't meet your criteria
with something like this:

@records.each { |record| record.destroy if/unless # insert your logic
here }

-- Josh
http://iammrjoshua.com


Me wrote:
> I have a table of data that I update with a file.  I would like to
> delete all data that does not get updated.
8133ee52ca72188132b5c7d97dfb967f?d=identicon&s=25 Me (Guest)
on 2009-01-05 22:55
(Received via mailing list)
Well that is the problem i need to find out which record have not been
updated so i can delete them.  How do i do that?

On Jan 5, 3:50 pm, Joshua Abbott <rails-mailing-l...@andreas-s.net>
A82ba1167f4d4a8d1de63820e576a87f?d=identicon&s=25 Robby Russell (Guest)
on 2009-01-06 00:23
(Received via mailing list)
On Mon, Jan 5, 2009 at 12:32 PM, Me <chabgood@gmail.com> wrote:
>
> I have a table of data that I update with a file.  I would like to
> delete all data that does not get updated.

We've done stuff like this before. One pattern that we used was:

1) At the beginning of the import process, we'd set a unique value
(like a timestamp/date)
2) We'd update an attribute in the table for all records with that
value:

example: last_import = 20081231

3) then run your import/update process..
4) then delete any records that last_import != 20081231

voila!

Robby

--
Robby Russell
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