That did the trick: I was over-enthusiastic in my usage of die(mysql_error).
I initially used mysql_error to troubleshoot another problem (which has now
re-emerged), but that's a different question which is puzzling me. The error
message ($alert = "Username already exists!";) displays on the page as soon
as the value has been inserted into mysql. It's strange, since the message
should be bypassed through the else statement, and the script only runs if
the user clicks 'submit'. Is this familiar?
> $check = mysql_query("SELECT * FROM user WHERE
> user_name='$user_name'") or die ("Unable to query
database:".mysql_error());
>
> $numrows = mysql_num_rows($check) or die ("Unable to search
> database:".mysql_error()); -----> DIES HERE when a new value is entered.
no
> mysql_error msg.
bla bla or die("more bla");
is a very bad way of handling error checks. In your particular case,
your foot has been shot off because mysql_num_rows will return 0 (no
rows match the query) and thus the die() is executed - but of course
there's no error in the query, it executed just fine, this we know
already.
Moral: don't use ' or die();' for anything else than hands on debugging
purposes
Regards
Peter
2011/5/30 Peter Lind <peter.e.lind@xxxxxxxxx>
> On 30 May 2011 22:31, Nazish <nazish@xxxxxxx> wrote:
> > Hi all,
> >
> > I've run into a little barrier, and I'm wondering whether you have any
> > insights. I'm entering values into a MySQL database. Before running the
> > mysql_query, I'm checking if the value already exists (using
> mysql_num_rows
> > == 0). If the value already exists in the database, the page will echo
> > "Username already exists" and it won't insert the user's new value. It
> runs
> > that far, and echoes the message accordingly. However, if the username is
> > new, and does not exist in the database, the query dies (without leaving
> a
> > mysql error).
> >
> > I tried changing the Unique IDs in the database, but it doesn't seem to
> be
> > the issue. The syntax seems fine, as I used it for another similar page.
> Any
> > idea why it's dying?
> >
> >
> > $check = mysql_query("SELECT * FROM user WHERE
> > user_name='$user_name'") or die ("Unable to query
> database:".mysql_error());
> >
> > $numrows = mysql_num_rows($check) or die ("Unable to search
> > database:".mysql_error()); -----> DIES HERE when a new value is entered.
> no
> > mysql_error msg.
>
> bla bla or die("more bla");
>
> is a very bad way of handling error checks. In your particular case,
> your foot has been shot off because mysql_num_rows will return 0 (no
> rows match the query) and thus the die() is executed - but of course
> there's no error in the query, it executed just fine, this we know
> already.
>
> Moral: don't use ' or die();' for anything else than hands on debugging
> purposes
>
> Regards
> Peter
>
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