Managing Editions

About Editions and Edition-Based Redefinition

Edition-based redefinition enables you to upgrade an application's database objects while the application is in use, thus minimizing or eliminating down time. This is accomplished by changing (redefining) database objects in a private environment known as an edition. Only when all changes have been made and tested do you make the new version of the application available to users.

DBA Tasks for Edition-Based Redefinition

Table 17-1 summarizes the edition-related tasks that require privileges typically granted only to DBAs. Any user that is granted the DBA role can perform these tasks.

Setting the Database Default Edition

There is always a default edition for the database. This is the edition that a database session initially uses if it does not explicitly indicate an edition when connecting.

To set the database default edition: 

1. Connect to the database as a user with the ALTER DATABASE privilege.

2. Enter the following statement:

   ALTER DATABASE DEFAULT EDITION = edition_name;
   

Querying the Database Default Edition

The database default edition is stored as a database property.

To query the database default edition: 

1. Connect to the database as any user.

2. Enter the following statement:

   SELECT PROPERTY_VALUE FROM DATABASE_PROPERTIES WHERE 
      PROPERTY_NAME = 'DEFAULT_EDITION';
   
   PROPERTY_VALUE
   ------------------------------
   ORA$BASE
   

Using an Edition

If you want to view or modify objects in a particular edition, you must use the edition first. You can specify an edition to use when you connect to the database. If you do not specify an edition, your session starts in the database default edition. To use a different edition, submit the following statement:

ALTER SESSION SET EDITION=edition_name;

The following statements first set the current edition to e2 and then to ora$base:

ALTER SESSION SET EDITION=e2;
...
ALTER SESSION SET EDITION=ora$base;

Editions Data Dictionary Views

There are several data dictionary views that aid with managing editions. The following table lists three of them. For a complete list, see Oracle Database Advanced Application Developer's Guide.