SQL> CREATE TABLE stock (item VARCHAR2(10), seq NUMBER, amt NUMBER);
 
Table created
SQL> ALTER TABLE stock ADD CONSTRAINT stock_pk PRIMARY KEY (item, seq);
 
Table altered
SQL> create materialized view log on stock WITH ROWID (item, seq, amt) INCLUDING NEW VALUES;
 
Materialized view log created
SQL> CREATE MATERIALIZED VIEW stock_v REFRESH FAST ON COMMIT
  2  AS SELECT item, SUM(amt) total_amt
  3  FROM stock
  4  GROUP BY item;
 
Materialized view created
SQL> ALTER TABLE stock_v ADD CONSTRAINT stock_v_chk CHECK (total_amt >= 0);
 
Table altered
 
SQL> INSERT INTO stock (item, seq, amt) VALUES ('A', 1, 1000);
 
1 row inserted
 
SQL> commit;
 
Commit complete
 
SQL> INSERT INTO stock (item, seq, amt) VALUES ('A', 2, -500);
 
1 row inserted
 
SQL> INSERT INTO stock (item, seq, amt) VALUES ('A', 3, -500);
 
1 row inserted
 
SQL> commit;
 
Commit complete
 
SQL> select * from stock;
 
ITEM              SEQ        AMT
---------- ---------- ----------
A                   1       1000
A                   2       -500
A                   3       -500
 
SQL> INSERT INTO stock (item, seq, amt) VALUES ('A', 4, -500);
 
1 row inserted
 
SQL> commit;
 
commit
 
ORA-12008: error in materialized view refresh path
ORA-02290: check constraint (OPS$TAGTRAK.STOCK_V_CHK) violated
 
SQL>