In Sybase ASE you can't directly set @@error
or use raiseerror
with a string.
Use sp_addmessage
to add custom error numbers and messages to your database. Once the error is listed, you can then reference it using the raiserror error_#
Sybase ASE reserves error numbers 20,000 and below for system use, so user defined errors can start at 20,001
More detailed information on raiserror
can be found in the documentation.