Beginning Microsoft SQL Server 2008 ... - S3 Tech Training

Chapter 12: Stored Procedures
All the parameters mean pretty much the same thing that they did with RAISERROR, except for the addition
of the language and replace parameters and a slight difference with the WITH LOG option.
@lang
This specifies the language to which this message applies. What’s cool here is that you can specify a separate
version of your message for any language supported in syslanguages.
@with_log
This works just the same as it does in RAISERROR in that, if set to TRUE, the message will be automatically
logged to both the SQL Server error log and the NT application log when raised (the latter only when
running under NT). The only trick here is that you indicate that you want this message to be logged by
setting this parameter to TRUE rather than using the WITH LOG option.
@replace
Be careful of this one in the Books Online. Depending on how you read it, it would
be easy to interpret it as saying that you should set @with_log to a string constant of
‘WITH_LOG’, when you should set it to TRUE. Perhaps even more confusing is that
the REPLACE option looks much the same, and it must be set to the string constant
rather than TRUE.
If you are editing an existing message rather than creating a new one, then you must set the @replace
parameter to ‘REPLACE’. If you leave this off, you’ll get an error if the message already exists.
Creating a set list of additional messages for use by your applications can greatly
enhance reuse, but more importantly, it can significantly improve readability of
your application. Imagine if every one of your database applications made use of a
constant list of custom error codes. You could then easily establish a constants file (a
resource or include library, for example) that had a listing of the appropriate errors;
you could even create an include library that had a generic handling of some or all
of the errors. In short, if you’re going to be building multiple SQL Server apps in the
same environment, consider using a set list of errors that is common to all your applications.
Keep in mind, however, that many system administrators do not like applicationspecific
changes to affect the master database (which is where your custom error
message is written), so if you are not in control of your own server, make sure that
custom error messages will be allowed on the server before writing code that depends
on them.
Using sp_addmessage
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As has already been indicated, sp_addmessage creates messages in much the same way as we create ad
hoc messages using RAISERROR.