Posts tagged ebr
OOW 2009: The killer feature of Oracle Database 11gR2 – Edition Based Redefinition (or database object versioning)
Today I presented on what is possibly the hottest story on the Oracle Database 11gR2 release: Edition Based Redefinition (EBR). EBR allows us to add a whole new dimension to the database – the Edition (that complements the existing dimensions of schema and object type). Every database object (well, almost every database object – not tables!) can have different implementations/incarnations/versions in various editions. The object versions are all in the same schema – they only differ in the Edition they are created in.
The Edition Based Redefinition has us create Editions in the database – cross database object spaces where new versions of existing database objects can be created – and others can just be inherited from previous editions. We can construct an Edition in isolation – no one is impacted by us creating new objects and versions of objects; objects can be invalid in that edition and no one will know anything about it. Only once the edition is complete, valid and tested can we make it available to new user sessions to work against. Using a simple alter session set edition statement, sessions can specify which edition they want to run against. That is: after the user has More >
Introducing Oracle 11gR2 Edition Based Redefinition or: On Parallel Application Universes
One of the most spectacular new facilities in Release 2 of the Oracle 11g Database is called Edition Based Redefinition – not a name perhaps that suggests any spectacle. EBR (Edition Based Redefinition) is a mechanism that allows on line application upgrade with no planned downtime. In short, the new release is built up in parallel to the existing one, in the same schema and using the same database objects; only the new (modified) objects live in another dimension and do not impact the existing objects. Once the entire set of new and changed objects has been created and recompiled, the database administrator can start routing new sessions to the new release; existing sessions can continue to run against the original set of objects – and new sessions if so desired can also run against the orginal set.
A set of object versions – mutually consistent and interdependent – which in software engineering terms would be duped a release or stripe and in Oracle Software Configuration Manager (Designer) terms a configuration is called an edition in 11gR2 lingo. An Edition is a combination of new objects, new versions of objects and inherited pre-existing versions that together make up a More >
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