CREATE OR REPLACE TRIGGER FOO_TRG1
BEFORE INSERT
ON FOO
REFERENCING NEW AS NEW OLD AS OLD
FOR EACH ROW
BEGIN
IF :NEW.FOO_ID IS NULL THEN
SELECT FOO_SEQ1.NEXTVAL INTO :NEW.FOO_ID FROM DUAL;
END IF;
EXCEPTION
WHEN OTHERS THEN RAISE;
END FOO_TRG1;
/
ALTER TRIGGER FOO_TRG1 ENABLE;
例如：
sql> declare 2 v number; 3 begin 4 select 1 into v from dual; 5 select 'a' into v from dual; 6 exception 7 when others 8 then 9 raise; 10 end; 11 / declare * ERROR at line 1: ORA-06502: PL/sql: numeric or value error: character to number conversion error ORA-06512: at line 9
VS：
sql> declare 2 v number; 3 begin 4 select 1 into v from dual; 5 select 'a' into v from dual; 6 end; 7 / declare * ERROR at line 1: ORA-06502: PL/sql: numeric or value error: character to number conversion error ORA-06512: at line 5
第一行中的行号指向加注而不是实线号.它可以使跟踪错误更难.
