Oracle provides a
wide variety of table types. The default table type is heap-organized. For most
applications, a
heap-organized table is an effective structure for storing and retrieving data.
However,
there are other
table types that you should be aware of, and you should know the situations
under which
each
table type should be implemented. Table 1-1 describes each table type and its
appropriate use.
In most scenarios, a
heap-organized table is sufficient to meet your requirements. This Oracle table
type
is a proven
structure used in a wide variety of database environments. If you properly
design your
database (normalized
structure) and combine that with the appropriate indexes and constraints, the
result should be a
well-performing and maintainable system.
Normally most of
your tables will be heap-organized. However, if you need to take advantage of a
non-heap feature
(and are certain of its benefits), then certainly do so. For example, Oracle
partitioning
is a scalable way to
build very large tables and indexes. Materialized views are a solid feature for
aggregating and
replicating data. Index-organized tables are efficient structures when most of
the
columns are part of
the primary key (like an intersection table in a many-to-many relationship).
And
so
forth.
Thank For Good Information From Good Oracle Book "Oracle.Database.11g.Performance.Tuning.Recipes"
Hope this help you to more understand :D
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