Re: Database exceptions

["Ilya A. Volynets-Evenbakh" <ilya@total-knowledge.com>]

Thanks.

What do you think about making explicit transactions, starting one
when connection is retrieved from the pool, and ending it when it
is released back? (Question here is: how do we decide if we need
to commit the transaction or roll it back. Does explicit transaction
get rolled back if an exception is thrown by a stored proc?)

Ilya.

Alexey Parshin wrote:
> Ilya,
>
> The database exceptions are thrown in several different situations. 
> This includes both read-only data access and data modifications. 
> Normally, exceptions thrown by the stored procedures (any data access 
> is done through stored procs) are re-thrown by sptk::CQuery as 
> sptk::CException.
>
> By the definition, any call of the stored procedure is a transaction. 
> If the exception is thrown from within the stored procedure, the 
> transaction is terminated and rolled back by PG server, to the state 
> before the procedure call. If no exceptions are thrown, stored proc 
> exits and transaction is committed by PG server.
>
> The exception from the above rule is the manual transaction start 
> (using CTransaction) and performing several procedure calls followed 
> by explicit commit (rollback happens on exceptions), but this isn't 
> used in UU at this point.
>
> 2008/12/23 Ilya A. Volynets-Evenbakh <ilya@total-knowledge.com 
> <mailto:ilya@total-knowledge.com>>
>
>     Alexey,
>
>     I have a few questions regarding UU database.
>
>     What happens if database exception is thrown in UU?
>     Does anything rollback? To what point?
>     Also, when does commit of a transaction happen?
>
>       Ilya.
>
>
>
>
> --
> Alexey Parshin,
> http://www.sptk.net