Saturday, April 5, 2008

How does one use the import/export utilities?

exp/imp allow to transfer the data across databases that reside on different hardware platforms and/or on different Oracle versions. If the data is exported on a system with a different Oracle version then on that on which it is imported, imp must be the newer version. That means, if something needs to be exported from 10g into 9i, it must be exported with 9i's exp.

In order to use exp and imp, the catexp.sql script must be run. catexp.sql basically creates the exp_full_database and imp_full_database roles. No need to run catexp.sql for every time. It is only one time work. It is already executed if you create your database by dbca. So , don't bother with it if you create database with dbca.
It is found under $ORACLE_HOME/rdbms/admin.

Prerequisites
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One must have the create session privilege for being able to use exp. If objects of another user's schema need to be exported, the EXP_FULL_DATABASE role is required.

Export/Import Modes:
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1)Full database export:
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The EXP_FULL_DATABASE and IMP_FULL_DATABASE, respectively, are needed to perform a full export.
Use the full export parameter for a full export.

2)Tablespace:
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Use the tablespaces export parameter for a tablespace export. It is only apply to transportable tablespaces.

3)Schema:
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This mode can be used to export and import all objects that belong to a user.Use the owner export parameter and the fromuser import parameter for a user (owner) export-import.

4)Table:
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Specific tables (and partitions) can be exported/imported with table export mode.
Use the tables export parameter for a table export.


Example:
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The following examples demonstrate how the imp/exp utilities can be used:

exp scott/tiger file=emp.dmp log=emp.log tables=emp rows=yes indexes=no
exp scott/tiger file=emp.dmp tables=(emp,dept)

imp scott/tiger file=emp.dmp full=yes
imp scott/tiger file=emp.dmp fromuser=scott touser=scott tables=dept

Using a parameter file:

exp userid=scott/tiger@orcl parfile=export.txt

... where export.txt contains:

BUFFER=100000
FILE=account.dmp
FULL=n
OWNER=scott
GRANTS=y
COMPRESS=y

To see DDL within Dump:
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To write ddl into a file,
imp userid/pass file=a.dmp indexfile=myfile.txt

or, to see ddl into screen,
imp userid/pass file=a.dmp show=y

Related Documents:
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Data Pump Export/Import
Export/Import from Enterprise Manager
Original Export/Import
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