Posts tagged flashback
Flashback started out as a feature in Oracle Database 9i. Although to be honest it is just the opening up of a mechanism that has been at the core of the Oracle Database from very early on: the ability to have concurrent sessions and transactions and allow transaction rollback and long running queries unaffected by transactions completed after the start of the query are all based on the same mechanism as flashback.
Flashback was great for demos and it was great for administrators. Developers however could not to very much with it. At least not until Oracle Database 11g when the Flashback Data Archive was introduced that provided fine grained control over which tables should have flashback data associated with it and which would not. At the time, the FDA was part of the Advanced Compression Database Option on top of the Enterprise Edition. So:great feature but for the happy few. In addition, there still were two main limitations with Flashback: history starts only at the day when the FDA is created. Nothing from before that day would be available. It’s a bit like the butterfly that does not have any of the memories of the caterpillar. The second limitation: Flashback did not record More >
I have just completed my first ever presentation on the Expertezed.com network – http://www.expertezed.com/ , a reprise from my session on Oracle OpenWorld 2012. This presentation includes a number of slides regarding 12c features, based on the session and slides from Tom Kyte (Top 12 new features) and my notes from the excellent session CON8511 – Temporal Database Capabilities with the Latest Generation of Database Technology that I attended during the conference.
You can download the slides from this presentation here:Expertezed_OOW2012_TheVeryVeryLatestInDatabaseDevelopment.pptx .
Database development in the Oracle Database is crucial for creating well balanced multi tier applications. This presentation describes a number of useful facilities and application architecture considerations around the database, taking into account some of the most recent insights.
The official slide deck from this presentation at Oracle Open World 2012:
Database Transaction Recorder – Adding Who to When and What to make Flashback take over from Journalling tables2
In previous articles, I have suggested that the arrival of the Flashback Data Archive in Oracle RDBMS 11g allowed us to finally say goodbye to journalling tables. Keeping track of all changes and previous states of our records in our own dedicated tables is no longer required, was my statement (for example in http://technology.amis.nl/blog/2453/oracle-11g-total-recall-flashback-in-the-hands-of-database-designers-and-application-developers-at-last-and-the-end-of-journalling-tables). Not only would using Flashback Data Archives require less programming, it improves performance for DML operations substantially and also provides a lot of functionality at our fingertips, as Flashback Queries easily incorporate historical records in straightforward SQL queries and using dbms_flashback we can even turn back time and regard all data as it was back then, using the same application and all the same queries.
In the not too distant past, Flashback knew quite a long list of limitations that made it almost impossible to make any changes to a table definition and still retain the historical data. With recent improvements in 11gR2, most of these limitations have been removed and DDL such as More >
When we were doing the APEX vs. ADF session at the last day of the ODTUG Conference yesterday, Dimitri showed a nice feature in APEX that allows you to use Oracle Flashback Queries to look not just at table data as it is right now, but also as it used to be in the recent past. That inspired me to see how easy it would be to do something similar for an ADF application. As an example of what you can do, I will create a simple web page in this article that will show an editable table with Employee records and below that a read only table that can show the data as it is right now, or as it was at some specific time in the last. Through a dropdown list, the user can select from which point in time the data should be retrieved. It allows for quick inspection of changes in data and could serve as a basis for recovering data (more…)