Prior to Oracle 10g, one of the only supported ways to move an Oracle database across platforms was to export the data from the existing database and import it into a new database on the new server.

Export / Import utility pretty well if your database is small, but can require an unreasonable amount of down time if your database is large. In Oracle 10g, the transportable tablespace feature has been enhanced in a way that makes it possible to move large databases (or portions of them) across platforms much more quickly and simply than the export/import method.

Note:
In Oracle 8i and Oracle 9i, tablespaces could only be transported into databases that ran on the same hardware platform and operating system. So if your Database ran on Windows and want to migrate on Linux , you could not use transportable tablespaces to copy data efficiently between the databases.

Beginning in Oracle 10g release 1, cross-platform support for transportable tablespaces is available for several of the most commonly used platforms. The process is similar to transporting tablespaces in previous Oracle releases, except there are a few possible extra steps, and there are more limitations and restrictions. Oracle 10g releases 2 goes one step further and offers the ability to transport an entire database across platforms in one step. But the limitations here are even stricter.

Important:

· Data pump cannot transport XMLTypes while original export and import can.
· Data pump offers many benefits over original export and import in the areas of performance and job management, but these benefits have little impact when transporting tablespaces because metadata export and import is usually very fast to begin with.
· Original export and import cannot transport BINARY_FLOAT and BINARY_DOUBLE data types, while data pump can.
· When original export and import transport a tablespace that contains materialized views, the materialized views will be converted into regular tables on the target database. Data pump, on the other hand, keeps them as materialized views.

Limitation:

· The source and target database must use the same character set and national character set.
· We can not transport a tablespace to a target database in which a tablespace with the same name already exists.
· Beginning with Oracle Database 10g Release 2, you can transport tablespaces that contain XMLTypes, but you must use the IMP and EXP utilities, not Data Pump. When using EXP, ensure that the CONSTRAINTS and TRIGGERS parameters are set to Y (the default).

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