Re: Re: Getting last record ID created from DB

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



markw@xxxxxxxxxxxxxx wrote:
markw@xxxxxxxxxxxxxx wrote:
On Sat, 2007-03-17 at 12:19 -0400, Mark wrote:

There in lies the biggest problem with LAMP, and that's MySQL. The
architecture of your methodology *only* works with MySQL, and not more
capable databases like Oracle, DB2, or even PostgreSQL.
I too thought the same thing, but was corrected when I starting working
on a redesign for the billing system for the company that I am working
for.  They use PostgreSQL and we do have a auto incremented unique id
field.  It isn't call AUTO_INCREMENT, but rather a sequence value.  It
is a value that is controlled by the default value entry.

It then runs this:
	nextval('customers_customer_id_seq'::regclass)

and uses this as the value of the id field for the newly inserted row.

Yea, I've been using PG for over 10 years now. Sequences are awesome, but
there have an "auto number" column type as well. It simply creates a
sequence but it's there.

I guess maybe most databases support the notion of "auto number" in some
form. I haven't used MSSQL recently, but I think their solution is a GUID.

Then instead of running a command like SELECT LAST_INSERT_ID(); you have
to do some other stuff like this:

$SQL = "SELECT currval('{$table}_{$column}_seq');";


Again, this is absolutely wrong unless it is wrapped in a transaction. You
will need a "begin" and a "commit" in an MVCC type system. If you don't
wrap it in a transaction you don't know who got the last "nextval" of the
sequence.

Check the documentation - currval returns the last one *for that session* - it does not return the last global change.

http://www.postgresql.org/docs/current/static/functions-sequence.html

It is perfectly safe to use this.

--
Postgresql & php tutorials
http://www.designmagick.com/

--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php


[Index of Archives]     [PHP Home]     [Apache Users]     [PHP on Windows]     [Kernel Newbies]     [PHP Install]     [PHP Classes]     [Pear]     [Postgresql]     [Postgresql PHP]     [PHP on Windows]     [PHP Database Programming]     [PHP SOAP]

  Powered by Linux