Why does a ORA-12054 error occur when creating this simple materialized view example?

Question

ALTER TABLE RECORDINGS ADD PRIMARY KEY (ID);

CREATE MATERIALIZED VIEW LOG ON RECORDINGS TABLESPACE USERS NOLOGGING;

DROP MATERIALIZED VIEW REC_SEARCH_TEST;
CREATE          


        

Answer 1

"Perhaps the example isn't the best, because I want to expand the view to a more complicated query that will require a distinct keyword, right now I am just trying to get it working on a basic level. "

The DISTINCT is the cause of the ORA-12054.

SQL> CREATE MATERIALIZED VIEW REC_SEARCH_TEST
    REFRESH COMPLETE ON COMMIT
    AS (
       SELECT DISTINCT empno, ename FROM emp
   )
/
  2    3    4    5    6  
       SELECT DISTINCT empno, ename FROM emp
                                         *
ERROR at line 4:
ORA-12054: cannot set the ON COMMIT refresh attribute for the materialized view


Elapsed: 00:00:01.14
SQL> SQL> 
SQL> CREATE MATERIALIZED VIEW REC_SEARCH_TEST
    REFRESH COMPLETE ON COMMIT
    AS (
       SELECT empno, ename FROM emp
   )
/
  2    3    4    5    6  
Materialized view created.

Elapsed: 00:00:02.33
SQL> 

Why not start with a something that works? Remove the DISTINCT. Get your MView working. Then complicate it later when it becomes necessary.

Although, as you already know you cannot use a DISTINCT you will have to revise either your query's logic or your refresh strategy.