The Logical Database Structure of an Oracle include :
> The schema objects,
> Data blocks,
> Segments and
> schema objects : means table, index, synonyms, sequences etc.
> Data blocks : are the smallest part of the oracle database defined by DB_BLOCK_SIZE parameter.
> Extent : A group of data blocks forms an extent.
> Segments : An extents groups tends to segments,
> Table space : lastly a group of segment forms a tablespace.