Its up to you to rollback the transaction. It would return a SQLITE_BUSY, not an IOERR.
Richard Klein <[EMAIL PROTECTED]> wrote: But am I correct in assuming that one way that SQLite provides serializable transactions is by automatically rolling back transactions when necessary (and returning SQLITE_IOERR)? Thanks, - Richard Klein [EMAIL PROTECTED] wrote: > Ken wrote: >> BEGIN TRANSACTION; >> SELECT balance FROM accounts WHERE accountId = '123-45-6789'; >> UPDATE accounts SET balance = >> WHERE accountId = '123-45-6789'; >> COMMIT; >> >> This is a comman and naive assumption that the balance selected >> will remain consistent. >> > > Actually, SQLite does provide this guarantee. Nothing in > the database will change during a transaction, except for > changes caused by INSERT, UPDATE, and DELETE statements > that occur within the transaction itself. It is not > possible for another process to modify the value of the > "balance" in between the SELECT and the UPDATE in the > SQL above. > > This is true of SQLite because isolation in SQLite > is "SERIALIZABLE". This is the highest level of isolate > provided by SQL. Most client/server database engines > by default implement "READ COMMITTED". The value of > "balance" might change between the SELECT and the > UPDATE in MySQL, for example. (I'm less clear about > what happens in PostgreSQL and Oracle. The point is > that your mileage may vary so be cautious.) > > But SQLite gets this right. Transactions are fully > serializable, which means they appear as if the entire > transaction happens instanteously with no chance for > outside processes to change values in the middle of a > transaction. > > -- > D. Richard Hipp > > > ----------------------------------------------------------------------------- > To unsubscribe, send email to [EMAIL PROTECTED] > ----------------------------------------------------------------------------- > ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
