In 2011 at the Oracle OpenWorld conference, I attended a presentation of  Kent Graziano about Data Vault Modeling. It was the first time I heard of this special modeling method for Data Warehouses, and after this session I was a bit confused about these...

Martin Preiss wrote a very positive review about our book " Data Warehousing mit Oracle - Business Intelligence in der Praxis ". Thank you to Martin for the positive feedback, but also for the improvement tips. For example he claimed that the...

For the third time, Trivadis is organizing the CBO Days , a brilliant event for everybody who is interested in performance tuning on Oracle databases. The list of speakers contains the "crème de la crème" of Oracle performance specialists: ...

This week I had the pleasure to attend the Kimball Group course " Dimensional Modeling in Depth " in Amsterdam. The course was given by Ralph Kimball and Margy Ross, the authors of the book " The Data Warehouse Toolkit " and many other...

Last week I got an interesting question from a former colleague: How can interval partitioning in Oracle 11g be combined with partition exchange? With interval partitioning, it is not possible to create a new partition manually. Usually, this is what...

A few months ago I wrote in a blog post that incremental statistics cannot be combined with a small value for estimate_percent . Because this problem is still an issue for one of my customers (who runs a quite big Data Warehouse) I was looking for some...

In the last three months I wrote some articles for Trivadis about miscellaneous design patterns for Data Warehouses. All the articles are based on practice experience of several customer projects. Because most of our customers are in Switzerland, Germany...

The slides of my OpenWorld presentation " Data Warehousing and Bitmap Indexes: More Than Just Some Bits " are now available in the Trivadis Download Area .

At the Oracle DEMOgrounds I talked to Robert Costin Velisar, Director of Software Development for Oracle Data Integrator. I asked him about the planned integration of Oracle Warehouse Builder (OWB) and Oracle Data Integrator (ODI) and wanted to know what...

In the Moscone West building at the OpenWorld, there is a bookstore full of Oracle books (they also have Oracle teddy bears, Oracle T-shirts, Oracle bags, Oracle water bottles and other advertising stuff). I spent some of my rare spare time between the...

In his OOW session, Joze Senegacnik called them ironically the "bitter old men": the members of OakTable that still run queries on V$-views in SQL*Plus instead of using Enterprise Manager. But the fact is that they are not only some of the most...

The organizers of the OpenWorld are very proud about their investment to save the environment by recycling PET bottles and using dishes made out of paperboard instead of plastic. This is definitely a good beginning, but there are still a lot of other...

The approach is not really new: To avoid disk access and improve performance, load all of your data into memory. I remember the cool feature called "RAM disks" on an  Apple][ when I went to school. A newer and much more sophisticated version...

In a few hours I will fly to San Francisco for the Oracle OpenWorld 2011 . I'm looking forward to this great event, and my personal schedule for the next days is filled with interesting sessions that I want to attend. At the moment, I do the last...

At the moment I'm working for a customer that installs all client computers with a German version of Windows. Ok, I can live with that. But unfortunately, all Oracle tools are installed by default in German as well. But I want to use the Oracle tools...

There are several solutions to load data from a source system into the Staging Area of a Data Warehouse. Usually, either database links or flat files are used to transfer the data between OLTP and DWH databases. A different, but very interesting approach...

Gathering optimizer statistics on a partitioned table usually needs a lot of time. To reduce this time, typically only a small percentage of the table and each partition is used for the calculation of the statistics. A value for the parameter  estimate_percent...

The Core is an important part of every Data Warehouse because it is used for the integration of data from different source systems. But is a Core really required in every DWH? As long as we have only one source system and one Data Mart, there is no...

In our book  Data Warehousing mit Oracle - Business Intelligence in der Praxis we describe a Data Warehouse architecture with four layers: The  Staging Area contains a copy of the last data delivery of each source system and is mainly used to...