In this method, you export
the data from the old version of the database and then import it into a database that uses the new
version of the Oracle software. This process may require disk space for multiple copies of the
data??”in the source database, in the Export dump file, and in the target database. In exchange for
these costs, this method gives you great flexibility in choosing which data will be migrated. You
can select specific tablespaces, schemas, tables, and rows to be exported.
In the Export/Import and Data Pump methods, the original database is not upgraded; its data
is extracted and moved, and the database can then either be deleted or be run in parallel with the
new database until testing of the new database has been completed. In the process of performing
the export/import, you are selecting and reinserting each row of the database. If the database is
very large, the import process may take a long time, impacting your ability to provide the upgraded
database to your users in a timely fashion. See Chapter 12 for details on the Export/Import and
Data Pump utilities.
NOTE
Depending on the version of the source database, you will need to
use a specific version of the Export and Import utilities. See the section
???Export and Import Versions to Use??? later in this chapter.
In the data-copying method, you issue a series of create table as select . . . or insert into . . .
select commands that cross database links (see Chapter 16) to retrieve the source data.
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