powerdesigner生成触发器错误

Question

SQL> drop trigger tib_table_20
2 /

drop trigger tib_table_20

ORA-04080: 触发器 'TIB_TABLE_20' 不存在
SQL> drop table Table_20 cascade constraints
2 /

drop table Table_20 cascade constraints

ORA-00942: 表或视图不存在
SQL> /*==============================================================*/
2 /* Table: Table_20 /
3 /==============================================================*/
4 create table Table_20 (
5 logid NUMBER(10) not null,
6 content VARCHAR(400),
7 constraint PK_TABLE_20 primary key (logid)
8 )
9 /

Table created
SQL> create trigger tib_table_20 before insert
2 on Table_20 for each row
3 declare
4 integrity_error exception;
5 errno integer;
6 errmsg char(200);
7 dummy integer;
8 found boolean;
9

10 begin
11 -- Column "logid" uses sequence Sequence_20
12 select Sequence_20.NEXTVAL INTO :new.logid from dual;
13

14 -- Errors handling
15 exception
16 when integrity_error then
17 raise_application_error(errno, errmsg);
18 end;
19 /

Warning: Trigger created with compilation errors

本来一直用的好好地，不知道怎么就突然这样了，求大神帮助