Submitted by Marcin Miller on Wed, 2006-02-01 18:00
Top-n Query is one of the more advanced SQL problems. How does one retrieve N first (or least) rows from a record set? For example, how does one find the top five highest-paid employees in a given department?
Submitted by Natalka Roshak on Sun, 2006-01-15 18:01
10gR1 revamped Oracle clustered database management and features. 10gR2 builds on this success with a long list of improvements and enhancements. Oracle has streamlined the installation process and provided more filesystem options, made some performance and monitoring improvements, and improved manageability with a half-dozen administration enhancements. This article will take a look at the major changes.
Submitted by Ellis Miller on Sat, 2006-01-07 06:39
This article shows how materialized views can be analyzed and optimized to ensure they can be FAST REFRESHed. As tools, the DBMS_MVIEW.explain_mview procedure and the MV_CAPABILITIES_TABLE are used. In this particular case, refresh time was reduced from more than 14 hours to less than 2!
Submitted by Marcin Moczyróg on Sun, 2005-12-25 18:01
The aim of this article is to describe the process of creating a user-defined aggregate function. Oracle 9i was used to prepare and test the function; some parts of the code may not work with Oracle versions older than 9i. This article gathers information that is needed to write the aggregate function in one place, and presents a clear step-by-step descripion of the process.
Submitted by Shouvik Basu on Fri, 2005-12-16 02:49
If there is a task in Oracle for which the wheel has been reinvented many times, it is that of generating database object DDL. There are numerous scripts floating in different forums doing the same thing. Some of them work great, while others work only until a specific version. Sometimes the DBAs prefer to create the scripts themselves. Apart from the testing overhead, these scripts require substantial insight into the data dictionary. As new versions of the database are released, the scripts need to be modified to fit the new requirements.
Starting from Oracle 9i Release 1, the DBMS_METADATA package has put an official end to all such scripting effort. This article provides a tour of the reverse engineering features of the above package, with a focus on generating the creation DDL of existing database objects. The article also has a section covering the issue of finding object dependencies.
Submitted by Natalka Roshak on Thu, 2005-12-01 23:55
Just about every DBA has had to deal with ora-1000 errors, "Maximum open cursors exceeded." This article will discuss initialization parameters that affect open cursors, the difference between open and cached cursors, closing cursors, and monitoring open and cached cursors.
Submitted by Shouvik Basu on Mon, 2005-10-24 10:36
This article introduces Oracle XML DB features to the DBAs and Developers who are not actively working with XML. It offers a quick start to those who finds quite a lot of Oracle XML literature around, and who is not sure where to begin.
Submitted by Steven Karam on Sun, 2005-10-16 19:00
In the rapidly shifting world of database technology, one fact has always been, and will always remain, true: a great database is no good if it can easily be broken into. A faulty security plan is not just vulnerable to hackers; it opens your company to data theft, corruption, or even legal action.
Submitted by Natalka Roshak on Sun, 2005-10-09 19:00
One of the primary tests for DBMS reliability is what's known as the ACID test. ACID-compliant systems are as close as you can get to guaranteed not to lose your data. Essentially, as long as your database files are intact, you are guaranteed that your data is consistent. This is not true for non-ACID compliant systems. Non-ACID-compliant systems are vulnerable to data inconsistency, and generally aren't taken seriously for any application where data integrity is important. Now, in 10gR2, Oracle offers us the option to break its ACID compliance.