The Data Warrior

Changing the world, one data model at a time. How can I help you?

05 May 2014

#OUGF14 Harmony by @ougf_ry

My buddy, Gurcan, the ODI Guru, did a great summary of the upcoming OUGF conference. I will be speaking there too about using Oracle Data Modeler, Data Vault, and Agile Data Warehousing.

I am looking forward to seeing Gurcan, Heli, and all my fellow Oracle ACEs in Helsinki. And looking forward to my first trip to Finland.

Come join the fun and learning this June.

gurcanorhan's avatarGurcan Orhan's ODI and DWH Blog

As some of you know, I will be attending to OUGF (Oracle User Group Finland) between 5-6th of June. Thanks to everybody who is in charge of paper selections especially Heli Helskyaho for the organization and Ann Sjökvist for the administration of the event.

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02 May 2014
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Data Vault 2.0 Training: Upcoming Public Classes

After my well-attended talk at #EDW14 in Austin this week (which was a GREAT event), a lot of you asked about where you could find a public class on Data Vault 2.0.

At the time I knew of none, but on my drive back home I was talking to Dan Linstedt (inventor of Data Vault) and he had great news for all of us: Dan will be teaching not one, but two public classes this summer!

Woohoo!

So the first one will be for all our friends in Europe. It will be June 2-4 in Helsinki, Finland. This will be a full 3-day Data Vault 2.0 Bootcamp class where you will get all the details on DV 2.0 modeling and methodology. If you want there is even an option to get the coveted CDVP2 after the class via a private certification exam.

This will be the 1st DV 2.0 class in Europe. So if you are in Europe, or have friends there, head over here for more details: http://danlinstedt.com/news/2014dv2bootcampfinland/

Following the class, Dan will be giving a keynote at the Oracle User Group Finland event on June 5-6 (I will be presenting there too!). To find out about OUGF check in over here: https://www.eventbrite.com/e/ougf-2014-harmony-tickets-10410222255 (scroll down to see the description and the agenda).

For the folks in USA and North America, Dan’s second public class will be  in Cincinnati, Ohio later in the summer. Details on this are not final yet. I will update this post as they become available.

So there you have it – DV 2.0 classes coming your way.

Cheers!

Kent

P.S. If these do not work for you you can always talk to Dan or myself about scheduling a private onsite class for you organization.

Posted in Data Modeling, Data Vault and tagged , , , ,
22 Apr 2014

After TROUG BI&DW 2014

Seems it is a busy spring for the Oracle User Group World. Meetings happening everywhere! I hope you all can find at least one event to attend in the first half of 2014. It is the best way to keep up with our constantly changing world and continue to bring value to your employers and customers.

gurcanorhan's avatarGurcan Orhan's ODI and DWH Blog

It was a nice day of TROUG BI&DW 2014 full day meeting. Thanks for all attendees, speakers and everybody who paid attention to this event.
Here are some blog posts / articles about event impressions.

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04 Apr 2014

This just in: Win Dinner with Monty at #KScope14

Amazing but true – you can now enter a contest to win dinner with ODTUG President Monty Latiolais at ODTUG’s annual conference KScope14.

This year KScope will be held in beautiful Seattle, Washington from June 22nd – 26th.

Who knows what amazing dinner adventure will be in store for the winner!

Get the details here:

Win Dinner with Monty!.

See you in Seattle!

Kent

The Oracle Data Warrior

P.S. I will be presenting again this year and running my now annual Morning Chi Gung class (more on that later)

Posted in ODTUG, Oracle and tagged , , , , , | Leave a comment
28 Mar 2014
15 Comments

Better Data Modeling: My Top 3 Reasons why you should put Foreign Keys in your Data Warehouse

This question came up at the recent World Wide Data Vault Consortium. Seems there are still many folks who build a data warehouse (or data mart) that do not include FKs in the database.

The usual reason is that it “slows down” load performance.

No surprise there. Been hearing that for years.

And I say one of two things:

1. So what! I need my data to be correct and to come out fast too!

or

2. Show me! How slow is it really?

Keep in mind that while getting the data in quickly is important, so is getting the data out.

Who would you rather have complain – the ETL programmer or the business user trying to run a report?

Yes, it has to be a balance, but you should not immediately dismiss including FKs in your warehouse without considering the options and benefits of those options.

So here are my three main reasons why you should include FK constraints in your Oracle data warehouse database:

  1. The Oracle optimizer uses the constraints to make better decisions on join paths.
  2. Your Data Modeling and BI tools can read the FKs from the data dictionary to create correct joins in the meta data of the tool (SDDM, Erwin, OBIEE, Cognos, Bus Objects can all do this).
  3. It is a good QA check on your ETL. (Yeah, I know… the ETL code is perfect and checks all that stuff, bla, bla, bla)

Now of course there are compromise options. The three main ones are I know:

  1. Drop the constraints at the start of the load then add them back in after the load completes. If any fail to build, that tells you immediately where you may have some data quality problems or your model is wrong (or something else changed).
  2. Build all the constraints as DISABLE NOVALIDATE. This puts them in the database for the BI tools and data modeling tools to see and capture but, since they are not enforced, they put minimal overhead on the load process. And, so I am told by those that know, even a disabled constraint helps the optimizer make a smarter choice on the join path.
  3. (really 2a) Best of both – disable the constraints, load your data, then re-enable the constraints. You get optimization and quality checks.

So NOW what is your reason for not using FKs in your data warehouse?

Happy Modeling!

Kent

Posted in Data Modeling, Data Warehouse, Oracle, SQL Developer Data Modeler and tagged , , , , , , , , , , , , , , , , , ,

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