Keyword & Parameter Description:
PRAGMA:
These keywords signify that the statement is a pragma (i.e. compiler directive). The Pragmas are processed at the compile time, not at the run time. They do not affect the meaning of the program; which simply convey the information to the compiler.
exception_name:
This identifies a user-defined exception formerly declared within the present scope.
error_number:
This is any of the valid Oracle error number. These are similar error numbers returned by the function SQLCODE.