When Oracle are adding a new feature to the database, they usually add a parameter to control it. Sometimes, after adding feature and the parameter, they realize that the parameter they chose for controlling the feature is not suitable. It might be confusing, or too general or something else. In these cases they change the parameter in the following version.
Starting with Oracle 12.1 we can export views as tables. This means that the export will contains a “create table” command and its data, while the original object was actually a view.
The LIKE operator is a very useful one. It is used to match strings with partial match while using the underscore (‘_’) as a single character wildcard and the percentage sign (‘%’) as multiple character wildcard.
When writing a query with order by, we can use the column position instead of its name. This order by”trick” is easy to use, but should be handled carefully as it affects the order of rows if the column list changes.
Many people are using DBMS_STATS to gather optimizer statistics. This package has many different options, and I wanted to tell you about one option for disabling automatic statistics gathering. When we need to disable the automatic statistics gathering we usually do one of the following:
When user A creates a procedure and grants execute permissions to user B, user B can execute the procedure (obviously), but he can also see the code (in ALL_SOURCE view).
If you are using Data Guard and standby databases, you probably need to do stuff based on the database role. For example, have some services start on the primary database, whichever that is. You might want to update some tables upon failover/switchover and more.