ошибка компиляции триггера в sqldeveloper с oracle11g

Question

Я изучаю триггеры от [http://www.tutorialspoint.com/plsql/plsql_triggers.htm][1] с sqldeveloper и я подключил базу данных Oracle 11g. Я создал таблицу клиентов успешно. Но когда я попытался создать триггер:

CREATE OR REPLACE TRIGGER display_salary_changes 
BEFORE DELETE OR INSERT OR UPDATE ON customers 
FOR EACH ROW 
WHEN (NEW.ID > 0) 
DECLARE 
    sal_diff number; 
BEGIN 
    sal_diff := :NEW.salary - :OLD.salary; 
    dbms_output.put_line('Old salary: ' || :OLD.salary); 
    dbms_output.put_line('New salary: ' || :NEW.salary); 
    dbms_output.put_line('Salary difference: ' || sal_diff); 
END; 

я получаю эти ошибки:

Error starting at line : 1 in command - 
CREATE OR REPLACE TRIGGER display_salary_changes 
BEFORE DELETE OR INSERT OR UPDATE ON customers 
FOR EACH ROW 
WHEN (NEW.ID > 0) 
    DECLARE 
    sal_diff number 
Error report - 
SQL Command: trıgger DISPLAY_SALARY_CHANGES 
Failed: Warning: yürütme uyarı ile tamamlandı 

Error starting at line : 7 in command - 
BEGIN 
    sal_diff := :NEW.salary - :OLD.salary; 
    dbms_output.put_line('Old salary: ' || :OLD.salary); 
    dbms_output.put_line('New salary: ' || :NEW.salary); 
    dbms_output.put_line('Salary difference: ' || sal_diff); 
END; 
Error report - 
ORA-06550: line 2, column 5: 
PLS-00201: identifier 'SAL_DIFF' must be declared 
ORA-06550: line 2, column 5: 
PL/SQL: Statement ignored 
ORA-06550: line 3, column 60: 
PLS-00487: Invalid reference to variable 'SQLDEVBIND1Z_2' 
ORA-06550: line 3, column 5: 
PL/SQL: Statement ignored 
ORA-06550: line 4, column 60: 
PLS-00487: Invalid reference to variable 'SQLDEVBIND1Z_1' 
ORA-06550: line 4, column 5: 
PL/SQL: Statement ignored 
ORA-06550: line 5, column 51: 
PLS-00201: identifier 'SAL_DIFF' must be declared 
ORA-06550: line 5, column 5: 
PL/SQL: Statement ignored 
06550. 00000 - "line %s, column %s:\n%s" 
*Cause: Usually a PL/SQL compilation error. 
*Action: 

Что не так с этим создать блок запуска?

Answer 1

Вроде бы тот же «Закрепление литералы» особенность, как описано здесь http://krisrice.io/2015-09-11-sqlcl-more-secure-now-with-rest/