mirror of
https://github.com/FirebirdSQL/firebird.git
synced 2025-01-22 20:03:02 +01:00
100 lines
2.4 KiB
Plaintext
100 lines
2.4 KiB
Plaintext
------------------
|
|
Exception handling
|
|
------------------
|
|
|
|
The common syntax rules for EXCEPTION statement is:
|
|
|
|
EXCEPTION [[name] [value]];
|
|
|
|
|
|
Run-time exception messages (FB 1.5)
|
|
------------------------------------
|
|
|
|
Function:
|
|
Allows to throw exceptions with text message
|
|
defined at runtime.
|
|
|
|
Author:
|
|
Dmitry Yemanov <yemanov@yandex.ru>
|
|
|
|
Syntax rules:
|
|
EXCEPTION <exception_name> <message_value>;
|
|
|
|
Scope:
|
|
PSQL
|
|
|
|
Example(s):
|
|
1. EXCEPTION E_EXCEPTION_1 'Error!';
|
|
2. EXCEPTION E_EXCEPTION_2 'Wrong type for record with ID=' || new.ID;
|
|
|
|
|
|
Exception re-raise semantics (FB 1.5)
|
|
-------------------------------------
|
|
|
|
Function:
|
|
Allows to re-initiate catched exception.
|
|
|
|
Author:
|
|
Digitman <digitman@hotbox.ru>
|
|
|
|
Syntax rules:
|
|
EXCEPTION;
|
|
|
|
Scope:
|
|
PSQL, context of the exception handling block
|
|
|
|
Example(s):
|
|
BEGIN
|
|
...
|
|
WHEN SQLCODE -802 DO
|
|
EXCEPTION E_ARITH_EXCEPT;
|
|
WHEN SQLCODE -802 DO
|
|
EXCEPTION E_KEY_VIOLATION;
|
|
WHEN ANY DO
|
|
EXCEPTION;
|
|
END
|
|
|
|
Note(s):
|
|
Evaluates to no-op if used outside the exception handling block.
|
|
|
|
|
|
Parameterized exceptions (FB 3.0)
|
|
---------------------------------
|
|
|
|
Function:
|
|
Allow to define exception message with slots for parameters and pass the parameters when
|
|
raising the exception.
|
|
|
|
Author:
|
|
Adriano dos Santos Fernandes <adrianosf at gmail.com>
|
|
|
|
Syntax:
|
|
EXCEPTION <name> USING ( <value list> )
|
|
|
|
Example:
|
|
create exception e_invalid_val 'Invalid value @1 for the field @2';
|
|
|
|
...
|
|
if (val < 1000) then
|
|
thing = val;
|
|
else
|
|
exception e_invalid_val using (val, 'thing');
|
|
end
|
|
|
|
Notes:
|
|
The maximum number of arguments passed is 9.
|
|
|
|
In the exception message, @NN (example: @10) is considered as @1 followed by the literal 0.
|
|
|
|
The status vector is generated using these codes combination:
|
|
isc_except, <exception number>,
|
|
isc_formatted_exception, <formatted exception message>, <exception parameters>
|
|
|
|
Since new error code (isc_formatted_exception) is used, it's necessary that the client is v3.0
|
|
or at least uses firebird.msg from v3.0 so that it can translate the status vector to string.
|
|
|
|
@N means the N parameter (where N starts at 1) passed in the exception raise command. If a N
|
|
parameter is not passed, the text is not substituted. If NULL is passed, it's replaced by string
|
|
'*** null ***'. If more parameters are passed than used in the exception message, they are
|
|
ignored.
|