[Zope] Concurrency/Atomicity in ZSQL/ZOracleDA ?

[Renaud Guérin]

En réponse à Casey Duncan <casey@zope.com>:

> This is a common operation. Most databases support a way to retrieve the
> last (or next) generated id for a table without resorting to using 
> max(id)+1. I would refer to your database documentation on this.

The DB is Oracle8 with ZOracleDA.

The trouble is, I need to generate this id in the first place, and as I said I'd
rather not use a sequence. Thus the max(id)+1

> As for concurrency, just make sure you perform both operations in a 
> single database transaction. Many database adapters automatically wrap
> each method call in a transaction. So by putting both sql statements in
> one ZSQL method (separated using <dtml-var sql_delimiter>) will do what
> you want. If the DA doesn't automatically do implicit transactions for
> you then just wrap the whole thing with "begin" and "end" SQL statements
> yourself.

thanks.
But what I want to make sure is that a transaction implies atomic operation, ie
nobody else can perform another select max(id)+1 before the select of the first
caller is performed.
Is that OK with my current setup ?