Use the RAISE statement to report messages and
raise errors.
RAISE level 'format' [, expression [, ...]];
Possible levels are DEBUG,
LOG, INFO,
NOTICE, WARNING,
and EXCEPTION.
EXCEPTION raises an error (which normally aborts the
current transaction); the other levels only generate messages of different
priority levels.
Whether messages of a particular priority are reported to the client,
written to the server log, or both is controlled by the
log_min_messages and
client_min_messages configuration
variables. See Chapter 17 for more
information.
Inside the format string, % is replaced by the
next optional argument's string representation. Write
%% to emit a literal %.
Arguments can be simple variables or expressions,
and the format must be a simple string literal.
In this example, the value of v_job_id will replace the
% in the string:
RAISE NOTICE 'Calling cs_create_job(%)', v_job_id;
This example will abort the transaction with the given error message:
RAISE EXCEPTION 'Nonexistent ID --> %', user_id;
RAISE EXCEPTION presently always generates
the same SQLSTATE code, P0001, no matter what message
it is invoked with. It is possible to trap this exception with
EXCEPTION ... WHEN RAISE_EXCEPTION THEN ... but there
is no way to tell one RAISE from another.
