ORA-12052 when create materialized view

Question

I following the sample in Oracle document to create materialized viewCREATE MATERIALIZED VIEW LOG ON sales
   WITH ROWID, SEQUENCE(amount_sold, time_id, prod_id)   INCLUDING NEW VALUES;
CREATE MATERIALIZED VIEW LOG ON times
   WITH ROWID, SEQUENCE (time_id, calendar_year)  INCLUDING NEW VALUES;
CREATE MATERIALIZED VIEW LOG ON products
   WITH ROWID, SEQUENCE (prod_id,prod_name)  INCLUDING NEW VALUES;
CREATE MATERIALIZED VIEW sales_mv
   BUILD IMMEDIATE   REFRESH FAST ON COMMIT
   AS SELECT t.calendar_year, p.prod_id, p.prod_name,
      SUM(s.amount_sold) AS sum_sales
      FROM times t, products p, sales s
      WHERE t.time_id = s.time_id AND p.prod_id = s.prod_id
      GROUP BY t.calendar_year, p.prod_id, p.prod_name; This works. BUt I actually does not want do aggregation. Thus I changed the MV creation statement toCREATE MATERIALIZED VIEW sales_mv
   BUILD IMMEDIATE REFRESH FAST ON COMMIT
   AS SELECT t.calendar_year, p.prod_id, p.prod_name,s.amount_sold
      FROM times t, products p, sales s
      WHERE t.time_id = s.time_id AND p.prod_id = s.prod_id;I got errorSQL Error: ORA-12052: cannot fast refresh materialized view GLU.SALES_MV
*Cause:    Either ROWIDs of certain tables were missing in the definition or
           the inner table of an outer join did not have UNIQUE constraints on
           join columns.
*Action:   Specify the FORCE or COMPLETE option. If this error is got
           during creation, the materialized view definition may have be
           changed. Refer to the documentation on materialized views.Please help or point me to the relevant document.
Thanks

Answer 1

damorgan, Thank you for you reply.
the inner table of an outer join did not have UNIQUE constraints on join columns.
I am not sure how much clearer and explanation can be written.If you look at the query, you will find that there is no outer join in the query.
sales table does not have unique constraints on prod_id and time_id. If this is the cause of the problem, I cannot change the data but is there a work around. That is way I ask for specific doc. In 11g documents, I only find some info on CREATE MV. That is mainly on syntax but not on requirement.