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.
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.
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.
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.
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.
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.
There are always a few topics in regards to writing SQL that always seem to come up more often than others. Querying data with case insensitivity is one of those topics. And Oracle has addressed this issue in many of their release. But in Oracle 10gR2 they have reached new levels. This article takes a dive into case insensitivity and how it is now handled in 10gR2. For the better!
DML error logging is a new feature for 10gR2. Have you ever tried to update 30 million records, only to have the update fail after twenty minutes because one record in 30 million fails a check constraint? Or, how about an insert-as-select that fails on row 999 of 1000 because one column value is too large? With DML error logging, adding one clause to your insert statement would cause the 999 correct records to be inserted successfully, and the one bad record to be written out to a table for you to resolve.
In this article Mark explais how one can drill from a "Discoverer for OLAP worksheet" to a "Discoverer Plus Relational worksheet" using Discoverer 10.1.2.