oracle简单存储过程以及如何查看编译错误

oracle简单存储过程以及如何查看编译错误
;

CREATE OR REPLACE PROCEDURE procedure_test IS
val VARCHAR2(200);
BEGIN
/* val := '';*/
SELECT uname INTO val FROM t_user;
END
;

select text from user_source where type='PROCEDURE' and name='PROCEDURE_TEST'
;

EXEC PROCEDURE_TEST;

execute procedure_test;

右键存储过程，重新编译；

然后执行
select * from SYS.USER_ERRORS where NAME = upper('PROCEDURE_TEST');
查看编译错误

；