Segments are the physical representation of the logical database
objects. A segment is thus a subunit of a tablespace, and will
be contained in a datafile. extents are subunits of a segment,
and are defined as contiguous sets of Oracle blocks. Successive
extents are not guaranteed to be contiguous, but within each
extent the Oracle blocks are contiguous. A block is the unit of
data that can be read or written to an Oracle data file, and is
managed using PCT_FREE and PCT_USED, among others.
[QUOTE][i]Originally posted by m_d_marian [/i] there are only
one segment for an object. Not necessarily so. A table (object)
can have partitions (subobjects), and partitions are segments.
So with partitioned tables and indexes you have more than one
segment for table/index. That means than an segment can be
spread on multiple files? [/B][/QUOTE] Jurij Modic ASCII a
stupid question, get a stupid ANSI 24 hours in a day .... 24
beer in a case .... coincidence?