On Oct 22, 2008, at 5:51 PM, Sean Thayne wrote:
not something to make a big deal over unless you are trying to
write an app
that supports both PostgreSQL and MySQL....
I'm working on making a php app work well with postgres...
in general sequences are much more efficient that auto_increment
techniques
How are they more efficient?
Go back and read my reply, you didn't quote the part where I explained
why they are more efficient :-) Ok, one more time:
Having something separate from tables makes the needed features much
easier and faster to implement. For general auto number features, no
matter how they are implemented, follow a similar process:
- Request for new number
- Lock on the entity handing out numbers to make sure there are no
duplicates
- Give out the new number
- Release the lock
If you've got to go digging through the table in order to that it's
more work that having a smaller, simpler object whose only purpose is
to hand out numbers (no potentially storing thousands/millions of rows).
There are also some specific limitations with how MySQL implements
auto_increment. For example, you are limited to one per table:
http://dev.mysql.com/doc/refman/5.1/en/create-table.html
When doing a multi-row insert you only get the id for the first record
inserted:
http://dev.mysql.com/doc/refman/5.0/en/example-auto-increment.html
Again, not usually the end of the world, just different. I'm a fan of
both, having used PostgreSQL (among a few other DBs) in a previous job
and using MySQL in my current job.
--
Joseph Scott
[EMAIL PROTECTED]
http://joseph.randomnetworks.com/
_______________________________________________
UPHPU mailing list
[email protected]
http://uphpu.org/mailman/listinfo/uphpu
IRC: #uphpu on irc.freenode.net
