Can i delete un-used rows from datafiles

[saqib]

How Can i delete un-used rows from datafiles in a tablespace and also let me know abt the 'defragmenting the database' and how can we done it.

Thanks in advance

[mike9]

I recommand you to have a look at the follwoing document to get a better understanding of an Oracle DB

http://download-uk.oracle.com/docs/cd/B14117_01/server.101/b10743/toc.htm