We are trying to create a datamart by keeping all the
tables as index organized, we started creating the
tables and found that for Index Organized Primary
key column is mandatory i.e you cannot create index
organized table unless you have a column with unique
values and a primary key on that column, any ideas
why primary key is required, we also have some
composite indexes on these tables since the tables
reside in Index table space what will be the impact
if we do not use the composite columns in a join
in sequence i.e the way the composite index is created.
anythoughts whether the query will use the index if
we do not use the composite key in the order they
have created.Please help as we are trying to do this
to improve performance of our queries and we found
in some instances that it is using 'Fast Full Index table
scan hint' and the queries are faster and some cases
they are not that effective.