Robert Treat wrote:
> On Thu, 2002-08-22 at 14:08, Kevin Brannen wrote:
>>I think you're missing the point of his request. Upgrading applications
>>(or anything binary) is trivial compared to upgrading a working
>>database, IMHO. (but maybe you just picked a bad analogy :-)
>>I don't see how you can keep a production DB running in any other way.
>>If you can, please let us know! But once a schema is being used in
>>production, and has a data in it, you can't just drop it and stuff a new
>>schema in; it needs to be transformed.
> Assuming you have maintenance windows for when you would be upgrading
> your database, there's no reason you have to rule out a full drop/reload
> of the database system.
Fair enough--some people have circumstances which allow this, I don't.
:-/ My maintanance windows are very small, and one day I will hit the
multi-million row size, creating a physical impossibility to drop/reload
in the time I have. And I suspect this is not an uncommon problem. :-)
>>And that's what the diff tool
>>does, helps to transform.
>>So he's not alone in his problem. Hope that helps you to understand
>>what he was asking for.
> Either method of upgrading is definitely valid under the right
> circumstances, but I would second any notion to keep entire schema
> versions in CVS and not just the "upgrades".
You bet! I always store the entire new schema. And I also create a
"transition" file that contains all the sql (creates and alters) to go
from one version to the next. A tool to help me create this transition
file would be a great thing! :-)
>>Hmmm, I wonder if I could write this... Ignoring constraint changes, it
>>doesn't sound that hard. If I do this, I'll post it to the news group.
> I am sure there are open source projects doing something similar to this
> now (perhaps even the mentioned mysql utility?) that could give you a
> jump start. If your doing this for 7.2.2, watch out for dropping
Good advice, I'll look around before I do anything. Yeh, the lack of
"alter table T drop column ..." is a real pain. If I write this tool,
I'll probably assume that command exists, which means the sql won't be
fully valid until PG7.3. :-(
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