When and why to perform a full database export.

* When there is a requirement to clone a database on another test or development server, then take a full database mode export dump and create a database with the similar settings of target database, and import the dump in source database.

Simple Steps: how to perform a full database export using export utility.

* Use either system user or any other database user who has the EXP_FULL_DATABASE privilege.
* Set the NLS_LANG environment variable according the database character set and language details.
SQL> select * from nls_database_parameters
2 where parameter in ('NLS_LANGUAGE','NLS_TERRITORY','NLS_CHARACTERSET');

PARAMETER VALUE
------------------------------ ----------------------------
NLS_LANGUAGE AMERICAN
NLS_TERRITORY AMERICA
NLS_CHARACTERSET WE8ISO8859P1

Windows (Dos Prompt):
C:\> set NLS_LANG=AMERICAN_AMERICA.WE8ISO8859P1

Unix/Linux:
$ export NLS_LANG=AMERICAN_AMERICA.WE8ISO8859P1

* Start the export with following command and options.

exp system/password@mydb file=c:\exportdmp\exp_fulldb_MYDB_27Aug08.dmp
full=y log= c:\exportdmp\exp_fulldb_MYDB_27Aug08.log

Note: This is just a simple export command to perform the full database export. I would request and suggest you to refer Oracle Documentations on export/import and their options. Check the references.

Help on Export and Import:

Windows:
C:\> exp help=y
C:\> imp help=y