Ci sono due condizioni che non sono soddisfatte per fare in modo che la vista materializzata si aggiorni velocemente. Il primo è che non hai specificato le colonne rowid di ogni tabella coinvolta. E la seconda è una restrizione non documentata:i join ANSI non sono supportati.
Ecco un esempio in cui DEPT è table_1, alias a ed EMP è table_2, alias b:
SQL> create materialized view log on emp with rowid
2 /
Materialized view log created.
SQL> create materialized view log on dept with rowid
2 /
Materialized view log created.
SQL> create materialized view empdept_mv
2 refresh fast on commit
3 as
4 select a.deptno
5 from dept a
6 left join emp b on (a.deptno = b.deptno)
7 /
from dept a
*
ERROR at line 5:
ORA-12054: cannot set the ON COMMIT refresh attribute for the materialized view
Questo imita la tua situazione. Per prima cosa aggiungi il rowid:
SQL> create materialized view empdept_mv
2 refresh fast on commit
3 as
4 select a.rowid dept_rowid
5 , b.rowid emp_rowid
6 , a.deptno
7 from dept a
8 left join emp b on (a.deptno = b.deptno)
9 /
from dept a
*
ERROR at line 7:
ORA-12054: cannot set the ON COMMIT refresh attribute for the materialized view
Tuttavia non può essere aggiornato rapidamente, a causa dei join ANSI. Conversione alla sintassi del join esterno vecchio stile:
SQL> create materialized view empdept_mv
2 refresh fast on commit
3 as
4 select a.rowid dept_rowid
5 , b.rowid emp_rowid
6 , a.deptno
7 from dept a
8 , emp b
9 where a.deptno = b.deptno (+)
10 /
Materialized view created.
E per dimostrare che funziona:
SQL> select * from empdept_mv
2 /
DEPT_ROWID EMP_ROWID DEPTNO
------------------ ------------------ ----------
AAARhmAAEAAAAI/AAB AAARhlAAEAAAAI3AAA 20
AAARhmAAEAAAAI/AAC AAARhlAAEAAAAI3AAB 30
AAARhmAAEAAAAI/AAC AAARhlAAEAAAAI3AAC 30
AAARhmAAEAAAAI/AAB AAARhlAAEAAAAI3AAD 20
AAARhmAAEAAAAI/AAC AAARhlAAEAAAAI3AAE 30
AAARhmAAEAAAAI/AAC AAARhlAAEAAAAI3AAF 30
AAARhmAAEAAAAI/AAA AAARhlAAEAAAAI3AAG 10
AAARhmAAEAAAAI/AAB AAARhlAAEAAAAI3AAH 20
AAARhmAAEAAAAI/AAA AAARhlAAEAAAAI3AAI 10
AAARhmAAEAAAAI/AAC AAARhlAAEAAAAI3AAJ 30
AAARhmAAEAAAAI/AAB AAARhlAAEAAAAI3AAK 20
AAARhmAAEAAAAI/AAC AAARhlAAEAAAAI3AAL 30
AAARhmAAEAAAAI/AAB AAARhlAAEAAAAI3AAM 20
AAARhmAAEAAAAI/AAA AAARhlAAEAAAAI3AAN 10
AAARhmAAEAAAAI/AAD 40
15 rows selected.
SQL> insert into dept values (50,'IT','UTRECHT')
2 /
1 row created.
SQL> commit
2 /
Commit complete.
SQL> select * from empdept_mv
2 /
DEPT_ROWID EMP_ROWID DEPTNO
------------------ ------------------ ----------
AAARhmAAEAAAAI/AAB AAARhlAAEAAAAI3AAA 20
AAARhmAAEAAAAI/AAC AAARhlAAEAAAAI3AAB 30
AAARhmAAEAAAAI/AAC AAARhlAAEAAAAI3AAC 30
AAARhmAAEAAAAI/AAB AAARhlAAEAAAAI3AAD 20
AAARhmAAEAAAAI/AAC AAARhlAAEAAAAI3AAE 30
AAARhmAAEAAAAI/AAC AAARhlAAEAAAAI3AAF 30
AAARhmAAEAAAAI/AAA AAARhlAAEAAAAI3AAG 10
AAARhmAAEAAAAI/AAB AAARhlAAEAAAAI3AAH 20
AAARhmAAEAAAAI/AAA AAARhlAAEAAAAI3AAI 10
AAARhmAAEAAAAI/AAC AAARhlAAEAAAAI3AAJ 30
AAARhmAAEAAAAI/AAB AAARhlAAEAAAAI3AAK 20
AAARhmAAEAAAAI/AAC AAARhlAAEAAAAI3AAL 30
AAARhmAAEAAAAI/AAB AAARhlAAEAAAAI3AAM 20
AAARhmAAEAAAAI/AAA AAARhlAAEAAAAI3AAN 10
AAARhmAAEAAAAI/AAD 40
AAARhmAAEAAAAI7AAA 50
16 rows selected.
La restrizione della sintassi ANSI-join è menzionata al punto 6 in questo post del blog .
Saluti, Rob.
