CREATE MATERIALIZED VIEW LOG ON WORKTASK WITH PRIMARY KEY INCLUDING NEW VALUES;

CREATE MATERIALIZED VIEW log ON ASSIGNMENTS WITH PRIMARY KEY INCLUDING NEW VALUES;

CREATE  MATERIALIZED VIEW REPORT_DATA_MV_INC
BUILD IMMEDIATE
REFRESH FAST ON DEMAND START WITH sysdate NEXT SYSDATE+1
DISABLE QUERY REWRITE
AS
SELECT t1.id, t2.id   FROM WORKTASK T1 
INNER JOIN ASSIGNMENTS T2 ON T1.SPEC_ID = T2.SPEC_ID 

Example 8-4 Materialized View Containing Only Joins

CREATE MATERIALIZED VIEW LOG ON sales
  WITH ROWID;
 
CREATE MATERIALIZED VIEW LOG ON times
  WITH ROWID;
 
CREATE MATERIALIZED VIEW LOG ON customers
  WITH ROWID;
 
CREATE MATERIALIZED VIEW detail_sales_mv 
       PARALLEL BUILD IMMEDIATE
       REFRESH FAST
       AS
       SELECT
       s.rowid "sales_rid", t.rowid "times_rid", c.rowid "customers_rid",
       c.cust_id, c.cust_last_name, s.amount_sold,
       s.quantity_sold, s.time_id
       FROM sales s, times t, customers c 
       WHERE  s.cust_id = c.cust_id(+) AND
              s.time_id = t.time_id(+);

CREATE MATERIALIZED VIEW LOG ON WORKTASK WITH ROWid;

CREATE MATERIALIZED VIEW log ON  ASSIGNMENTS WITH ROWID;

CREATE  MATERIALIZED VIEW REPORT_DATA_MV_INC
BUILD IMMEDIATE
REFRESH FAST ON DEMAND START WITH sysdate NEXT SYSDATE+1
DISABLE QUERY REWRITE
AS
SELECT t1.triidtx   FROM WORKTASK T1 
, ASSIGNMENTS T2 WHERE  T1.SPEC_ID = T2.SPEC_ID