Oracle is a powerful database management system that has been a go-to choice for many businesses and organizations around the world. It offers a wide range of features and functionalities that help users store, manage, and retrieve data efficiently. However, there are some hidden features in Oracle that many users are not aware of. In this article, we will uncover some of these hidden gems and explore how they can enhance your experience with Oracle.
1. Virtual Columns
Virtual columns are a relatively new feature in Oracle that allows you to create columns in a table that are not physically stored in the database. These columns are calculated on the fly based on the values of other columns in the same table. This feature can be useful in scenarios where you need to perform complex calculations on data without actually storing it in the database. Virtual columns also help improve query performance since the calculations are only done when the data is retrieved.
2. Invisible Indexes
Indexes are essential for optimizing query performance in Oracle. However, there are cases where an index may not be beneficial, and in some cases, it can even slow down the performance. With the introduction of invisible indexes, you can now create indexes that are not visible to the optimizer. This means that the optimizer will not consider these indexes when generating query execution plans, but they will still be available for manual use. This feature helps to improve the overall performance of the database by reducing the overhead of maintaining unnecessary indexes.
3. Flashback Data Archive
The flashback data archive feature in Oracle allows you to track and store historical changes made to a table. It works similarly to the traditional flashback query feature, but instead of just querying the data, you can restore it to a specific point in time. This feature is useful in scenarios where you need to recover accidentally deleted data or track changes made to sensitive data.
4. Edition-Based Redefinition
Edition-based redefinition is a unique feature in Oracle that allows you to make changes to the database schema while the system is still running. This means that you can make changes to tables, views, and packages without interrupting the application's availability. These changes are made in a separate edition, and once they are complete, you can switch the application to use the new edition seamlessly. Edition-based redefinition helps reduce downtime and allows for a more streamlined deployment process.
5. Automatic Big Table Caching
For databases with large tables, accessing data from these tables can be time-consuming and resource-intensive. The automatic big table caching feature in Oracle helps to improve the performance of these queries by caching frequently accessed data in the database's memory. This feature is especially useful for read-intensive workloads, and it can significantly improve query performance.
6. Pluggable Databases
Pluggable databases (PDBs) are a relatively new feature in Oracle that allows you to consolidate multiple databases into a single container database (CDB). Each PDB is a self-contained database that can be plugged into the CDB, making it easier to manage and maintain multiple databases. This feature also helps to reduce the hardware and software costs associated with managing multiple databases.
7. Application Continuity
Application continuity is a feature that helps to improve the availability of your application in the event of a failure. It works by capturing the state of your application before a failure occurs and replaying the transaction once the database is back online. This feature helps to ensure that your application can continue to function without any interruptions, even in the case of a database outage.
