Re: [boost] [rdb] 0.0.09

Subject: Re: [boost] [rdb] 0.0.09
From: Stefan Strasser (strasser_at_[hidden])
Date: 2009-09-28 20:19:35

Am Monday 28 September 2009 18:26:49 schrieb Jean-Louis Leroy:

> Of course I could say that all backends have three functions :
> start_transaction, commit and rollback. In the case of ODBC
> start_transaction would be a no-op. Or maybe it would turn auto-commit
> off (and throw if the underlying db is not tx-capable). But I am
> hesitating a bit. The current philosophy of my lib is much like C's :
> you look at any piece of code and you know exactly how it will translate
> into machine code. No hidden 17 dtor calls hidden inside a closing
> brace. From that point you either use rdb to write apps or as a
> foundation to build higher-level tools.
>
> OTOH maybe I'm splitting hairs wrt transactions. Besides the two
> patterns above, does anybody see a third possibility ? Nested
> transactions ? They fit nicely in the second pattern...

I'm not sure if the BEGIN/COMMIT syntax is supported by some vendors for 
nested transactions, but others defniitely only support SAVEPOINT/RELEASE.
so you'd have to break with your concern that you'd like the rdb SQL syntax 
look like what is executed under the hood anyway, if I understood it 
correctly.

another thing, probably minor at this stage, you might want to consider is 
2-phase-transactions, which would add an additional PREPARE statement, and a 
way to retrieve the transactions that are in prepare-state after a crash, to 
the interface.

see e.g. http://dev.mysql.com/doc/refman/5.0/en/xa-statements.html