Create materialized view log for fast refresh. Following materialized view script wont get executed if materialized view log doesn't exists
CREATE MATERIALIZED VIEW MAT_Employee_Incentive_Refresh
BUILD IMMEDIATE
REFRESH FAST ON COMMIT AS
select FIRST_NAME,max(INCENTIVE_AMOUNT) from EMPLOYEE a, INCENTIVES b
where a.EMPLOYEE_ID=b.EMPLOYEE_REF_ID group by FIRST_NAME
