In 12c a new SESSION level sequence can be created to support sequence values at session level. This feature can be usefull if you are working with global temporary tables that have session level existence. If you create a session level sequence you can create a unique range of values in your active session not…
Today i want to explain the new Histograms Enhancements in 12c. But first i want to explain some basic about basic about histograms, because i know that they are not well known by some DBA`s.The Optimizer normaly thinks that the data in a column is uniformly distributed. A example of this is a primary key column…
This new feature allows to transform an SQL statement that contains views. The result is a SQL statement in which the views are dissolved and integrated into the SQL.This support for the DBA to find application logic errors or performance problems. Here is a example where a query from your application and Views are used. In my…
A other nice new Feature is that you can now query Inventory details inside the Oracle Database. This is very usefull for example if you want to extend your Monitoring to monitor Patch details or when you want to compare two Oracle Home from sqlplus. The new Package DBMS_QOPATCH returns all Information as XML Document.…
Also some changes have done to the Password file in the New Oracle 12c Database. Password file can now be stored in the ASM. This feature eliminates the behavior where the sys Passwort is changed on one RAC site only and the DBA forget to change it on the other nodes or after a recover…
You can now create invisible columns in your database. This means that when you create such column, that this will not affect you application and you can fill it with data. When all preparation is done you can change it to a visible column. Sample for creating a table with invisible columns: CREATE TABLE…
From 12c onwards it seems that the resource role has changed. The UNLIMITED TABLESPACE privilege is no longer the default RESOURCE role starting in Oracle Database 12c. The change should increase the security, but will be a pitfall will be that many oracle customers create application users without quota. So be sure to check your…
A other new feature in 12c is the possibility to restore a table with rman. In a pre 12c for example you will do a Tablespace Point In Time Recovery (TPITR) to create a auxiliary database and then export your table from there. In 12c the steps are the same, but you will need a…
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