People use export because it is very easy to operate. There are very few command should be need to execute with export (exp help=y) command and it takes full Oracle database backup. Without knowledge of Oracle DBA operations also able to take backup of full Oracle database using export utility. Using export utility a file is generated calls Dump file because it has default extension .dmp.

Recovery of Oracle database is also simple from export. Import utility calls recovery utility of Oracle database. Import utility easily detects export dump file. Like export utility, import (imp help=y) utility has also very few commands to perform recovery of Oracle database.

Using import utility we can recover full database.

A characteristic of export and import utility is it can be done user level, table level or full database. Means we can take backup of single table or single user level or whole database and recovery can be performed using import in different level.

Export and Import becomes more popular due to easy to understand and easy to perform.

One problem I found that is we are not able to exclude some tables during full export backup or user level export backup. Some of tables are read only tables or never refresh. Then we should need to exclude those tables from our backup because it is useless to take backup of those tables again and again with same data. Unnecessary our export dump file becomes large.

When we are take full backup of database using export utility (exp full=y), same time we can't able to exclude some tables which really we don't want to take backup. Because export utility doesn't perform deselect any table in full database export or user level export. Using expdp we can exclude some table but this new feature was introduced in Oracle 10g. What about previous release?

Using one trick we can exclude some tables in export backup. Change sql of view exu10tab or exu9tab, it can be possible. Off course changing data dictionary view doesn't supported by Oracle, but we can able to perform our backup of Oracle database task for excluding some unwanted tables.

Use Oracle Enterprise Manager or Toad like utilities to change this sql statement  (definition) of data dictionary view.  Those are very easy options to modify such sql statement. It doesn't recommend to change this definition of Data Dictionary view because it is not supported by Oracle Support. This we can do for performing our important task when space usage is constraint in more important. From Oracle 10g expdp contain parameter named EXCLUDE. We can give list of tables which are wanted to not taking in backup for saving our disk space and not wasting time. But for past release of Oracle database this trick is useful to avoid such read only tables and unwanted table for saving disk space and saving time of backup of Oracle database.

All the Best,

Thanks and Regards,

Gitesh Trivedi

Dbametrix Solutions

About The Author:  Gitesh Trivedi is an Expert Oracle DBA and working in Dbametrix.  He has excellent 13 years experience. You can reach him on site http://www.dbametrix.com offers Remote DBA support and remote Oracle DBA service. All copyright reserved by @Dbametrix. contact mailto:info@dbametrix.com  or at http://www.dbametrix.com/remote-dba.html