Subject: Re: query does not affect database 2007-09-26 - By Jack Monflower
Back
Hi Warren,
Thanks for your (and Jim's) e-mail. Apparently the problem was mixing
exception and return codes together (I opened the connection with false, but
expected exceptions to be thrown. They weren't thrown, even though my query
resulted in an error).
It seems to be working now. Thanks again for your time.
On 9/26/07, Warren Young <mysqlpp@(protected)> wrote:
>
> Jack Monflower wrote:
> >
> > Connection goes fine (I check if connect returns false, and it does
> not).
>
> You can't mix the return-code and exception error handling mechanisms in
> this way.
>
> I don't mean to suggest that the connection could be failing. If it
> were, your program would be crashing because you aren't (apparently)
> catching the exception you'd get if that were happening. It is
> something you need to address to make this code production-ready, however.
>
> If you must mix the two error handling mechanisms, you need to use a
> NoExceptions object to temporarily turn off exceptions for a given block
> of code.
>
> > if (!conn.connect("mydb", "localhost", "root", ""))
>
> [snip]
>
> > Transaction trans(Configuration::conn());
>
> You're referring to the connection in two different ways here. Are you
> certain that these are the same connection?
>
> And I hope Configuration::conn() returns by reference? If not, that's
> probably the problem.
>
> > Everything goes well, compilation as well execution, and the program
> exits
> > with the message "user added". Still, when I check if anything was added
> to
> > the database, I see no new rows.
>
> Not all of the storage engines MySQL offers support transactions. Are
> you using one of them?
>
> Transactions are also relatively recent additions to MySQL. Are you
> using a version of MySQL that even supports transaction-aware storage
> engines?
>
> Does it work if you type the SQL for this insertion sequence into the
> mysql command line client?
>
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