IMHO it depends on your needs. Usually the 4th will try some sort of error recovery and if that fails, rollback itself. This bubbles up until it reaches the top.
-----Ursprüngliche Nachricht----- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Gesendet: Montag, 9. April 2007 19:50 An: sqlite-users@sqlite.org Cc: [EMAIL PROTECTED] Betreff: Fwd: Re: [sqlite] SQLite and nested transactions I'm still learning how databases and transactions work so bear with me. How does error handling work? If I have 5 nested transactions and the 5th transaction fails is this transaction failure supposed to be communicated to the parent or does the fourth transaction try to do error recovery? Ray > Date: Mon, 9 Apr 2007 9:38:16 -0700 > From: <[EMAIL PROTECTED]> > To: sqlite-users@sqlite.org > Cc: Dennis Cote <[EMAIL PROTECTED]> > Subject: Re: [sqlite] SQLite and nested transactions > > > So. If i read this code right. > * The transaction_level keeps track of how many nested transactions have occurred. > * Only the parent transaction allows the commit. > > In this case, only a single journal is required (the parent journal). > Thanks, > Ray > > > ---- Dennis Cote <[EMAIL PROTECTED]> wrote: > > Darren Duncan wrote: > > > > > > I will clarify that child transactions are just an elegant way of > > > partitioning a larger task, and that parent transactions always > > > overrule children; even if a child transaction commits > > > successfully, a rollback of its parent means there are no lasting changes. > > Darren, > > > > Because of this, and the fact that a transaction is basically a > > guarantee that all or none of the enclosed statements are executed, > > it is much simpler to implement nested transactions using a counter > > and the existing transaction API in a set of wrapper functions. > > There is no need to maintain all the intermediate state information. > > All you need to know is the current nesting level, and if any > > enclosed transaction was rolled back. > > > > The following code shows the basic process. > > > > int transaction_level = 0; > > bool transaction_failed; > > > > void begin_nested_transaction() > > { > > if (transaction_level++ == 0) { > > transaction_failed = false; > > sqlite3_exec("begin"); > > } > > } > > > > void commit_nested_transaction() > > { > > if (--transaction_level == 0) > > if (transaction_failed) > > sqlite3_exec("rollback"); > > else > > sqlite3_exec("commit"); > > } > > > > void rollback_nested_transaction() > > { > > transaction_failed = true; > > commit_transaction(); > > } > > > > HTH > > Dennis Cote > > > > -------------------------------------------------------------------- > > --------- To unsubscribe, send email to > > [EMAIL PROTECTED] > > -------------------------------------------------------------------- > > --------- > > > > > ---------------------------------------------------------------------- > ------- To unsubscribe, send email to > [EMAIL PROTECTED] > ---------------------------------------------------------------------- > ------- > ---------------------------------------------------------------------------- - To unsubscribe, send email to [EMAIL PROTECTED] ---------------------------------------------------------------------------- - ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
