Export and Import Utilities

Export(exp)  and import(imp) are Logical backup and Recovery. When exporting the database objects are dumped to a binary file which can then be imported into another Oracle database.

The Export and Import utilities provide a simple way for you to transfer data objects between Oracle databases, even if they reside on platforms with different hardware and software configurations. 

When you run Export against an Oracle database, objects (such as tables) are extracted, followed by their related objects (such as indexes, comments, and grants), if any. The extracted data is written to an export dump file. The Import utility reads the object definitions and table data from the dump file. First, let us see export in detail.

Difference between exp/imp and expdp/impdp

Exp/imp is a Traditional  export import,expdp/impdp is a Datapump export    
  import.

Traditional export import utility is starting with exp/imp,Datapump utility   
is starting with expdp/impdp. 

Datapump access files in the server (using ORACLE directories). Traditional export can 
access files in client and server both (not using ORACLE directories).

exp/imp (Traditional)  is using conventional path , expdp /impdb (Datapump) is using 
Direct path.

Exp (Traditional) is byte mode ,Datapump is block mode.

Data Pump will recreate the user, whereas the old imp utility required the DBA to
create the user ID before importing.

Datapump utility we can stop and Restart the Jobs.

Features of Datapump utility

Job Estimation can be Done in Datapump.

Data Remapping can be done using REMAPDATA parameter.

EXCLUDE and INCLUDE parameter allows the fine-grained object selection.

Failed export/import Jobs can be Restarted.

Export and import can be taken over the network using database links even 
without Generating the dump file using NETWORK_LINK parameter.


CONTENT parameter gives the freedom for what to export with options METADATA ONLY,
DATA, BOTH.

You don’t need to specify the BUFFER size in datapump

Job estimated completion time can be monitored from v$session_longops view.

Dump file can be compressed with COMPRESSION parameter. In conventional exp/imp you
have to compress the dumps using OS utilities.

Data encryption can be done in datapump.

DATAPUMP has interactive options like ADD_FILE, START_JOB, KILL_JOB, STOP_JOB.

REUSE_DUMPFILES parameter asks the confirmation/rewrite the existing dumpfile.

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