Given that even the most basic, multiuser apps hit concurrency issues with editing different fields in the same record, I was surprised that version locking was the only level of support Rails offered.
I would *love* to PDI field level change checking (I've done it before on another framework) and also updating Base to only UPDATE fields that have changed. While it may sound funny, I'm a gung-ho person and would just need to be pointed in the direction of how to make a plugin. I wander through the ActiveRecord code all the time but not all of Rails. I was pondering adding support with a patch and have some really great ideas but if it didn't get accepted, I didn't want to waste the time. Also, how do I check to see if someone else hasn't already started a plugin/gem/patch for the same issue?
I'm curious to know if "dirty" checking was considered during the design
process of AR. It would add performance benefits (configurable?) for larger
tables and associations in a write heavy environment especially if you have
text or blob fields in your tables. Anyone care to PDI this as a plugin?
Bob Silva
-----Original Message-----
Sent: Thursday, July 27, 2006 8:03 AM
Subject: Re: [Rails-core] Re: Why are has_one objects resaved when the
parentis saved?
On 2006-07-27, at 11:56 , Josh Susser wrote:
That's a valid point. But did you read Jonathan's patch? It covers that case where you're dealing with new records just fine. I think the issue he was correcting was that has_one *always* saves the child object, not just for new records.
Strictly, it does not *always* save the child, only if it's been *loaded*.
It checks the association ivar directly, meaning it does not go through the accessor, and therefore does not try to load it.
Saving loaded associations is a cheap way to make sure you save everytime a change *could have* happened. Without a dirtyness check, I'd say that's good enough.
The alternative would be a handcoded dirtyness check, something like:
assoc_record.class.find(record.id).attributes.all? { |(k, v)|
assoc_record.send(k) == v }
Which quickly becomes expansive.
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