Re: Getting error messages to the (PHP) user

On Tue, 05 Mar 2013 11:31:27 -0500
"Mark A. Hershberger" <[email protected]> wrote:

> On 03/05/2013 10:45 AM, James K. Lowden wrote:
> > Server messages arrive with a severity code.  By convention,
> > severity codes >= 10 are "errors" in the sense that the user can't
> > fix them.  
> 
> But I'm seeing the hard-coded message for errors in my SQL that *I*
> should fix.
> 
> For example, I was getting the hard-coded message till I patched the
> freetds library.  Now I see the following:
> 
>   $ php import-sql.php
>   Error: [HY000] Incorrect syntax near 'AUTO_INCREMENT'. [102]
>   (severity 15) [CREATE TABLE ...]
> 
> Yes, I know that this is MySQL code and I need MSSQL code.  The point
> here is that the error message and the severity and the severity (15 >
> 10) is the direct result of something I can fix.

Right.  The "user" they meant isn't you the programmer, but a user of
your application.  If the data entered fail a contraint, the user can
change the data and continue.  Broken SQL is a severe problem in a
production application, as I'm sure you agree!  :-)

It's not intended that you should have to change the FreeTDS code to
alter the error-handling characteristics.  db-lib itself never prints a
anything in response to a server message or a library error.  (This can
be frustrating to someone just learning, but as you see it's helpful.)
Instead, db-lib provides for the application -- in this case the PHP
library -- to install a callback function. Errors and messages are
passed to the installed function, which does what it does.  

If you look at the bsqldb application (src/apps/bsqldb.c) you'll see
calls to dberrhandle() and dbmsghandle().  The function definitions are
at the end of the source file.  

I don't know PHP.  To control the error reporting behavior, you need
either to change the callback function PHP installs, or somehow affect
what it does.  In applications I've written, for example, there was
sometimes a list of message numbers that were suppressed.  In your
case, it sounds like you probably want to log the details and report a
more naïve message.  (I'm not sure I support that idea, but that's
another question.)  

HTH.  

--jkl