Garry Gramm has found more information and a new video of Perceptive Pixel's wonderful computer interface.  I found a working copy of the video on Google Videos.

Can you imagine, instead of whiteboards, having this functionality on your walls?  No more copying, or photo graphing - just do the work once and refine it later.   I wonder what the agile folks would do with this?  Perhaps erase it right away?

We arrived in Boston on Sunday to attend the Wilshire Conferences' Meta-Data Conference and DAMA Symposium 2007.  This is my 10th DAMA Conference, I believe.

Sunday there were half day workshops, but due to the glories of air travel, we arrived late, so we skipped these events.  There were two I wanted to attend, so I was disappointed.

Monday offered full day workshops, so I spent time in Graeme Simsion's Consulting Skills workshop, John Zachman's Framework workshop, and Steve Hoberman's Data Modeling Challenges.

Today I am presenting on "Implementing Industry Standard Data Models". I have already attended the ERwin SIG, which I have posted about on the ERwin User Discussion Group.  Check out that group to see my reports. 7:15AM events are sometimes a bit strained for everyone.

Earlier this morning I attended Gordon Everest's presentation on ORM and NIAM.  I started my data modeling career working with NIAM.   This modeling technique leaves you with every fact as an object on a diagram.  I think it is important that data architects be familiar with all kinds of modeling techniques, so search Object Role Modeling (ORM).

Right now I'm sitting in Michael Ley's presentation on Globalization, Localization. Code Pages, Unicode, etc.  This presentation is very detailed and very informative.  Who knew that UPS supported Egyptian Hieroglyphics?

The next presentation I will be attending is Len Silverston's case study on culture and human dynamics.  Len has been working a great deal in this area.  I wish that IT educational programs focused more on these topics.

More to come.

Arthur Fuller, of Redgate, has written an article for the RedGate Simple Talk newsletter about database design for systems that have to preserve data - that don't delete data, but mark it as no longer current.

http://www.simple-talk.com/sql/database-administration/database-design-a-point-in-time-architecture/

Point in Time Architecture (PTA) is a database design that guarantees support for two related but different concepts – History and Audit Trail.

• History – all information, both current and historical, that as of this moment, we believe to be true.
• Audit Trail – all information believed to be true at some previous point in time.

The distinction is that the Audit Trail shows the history of corrections made to the database. Support for History and Audit Trail facilities are notably absent from typical OLTP databases. By "typical", we mean databases that support the traditional Select, Insert, Delete and Update operations. In many cases, typical OLTP databases are perfectly fine for their requirements, but some databases demand the ability to track History and Audit Trail as core requirements. Without these abilities, the database will fail.

Typical OLTP databases destroy data. This is most obvious with the Delete command, but a moment's thought reveals that the Update command is equally destructive. When you update a row in a table, you lose the values that were there a moment ago. The core concept in PTA is this: no information is ever physically deleted from or updated in the database.

 

 

Michael Coles has a couple of good articles on NULLs, ANSI, SQL Server, the Four rules of NULLs, and unknowns:

http://www.sqlservercentral.com/columnists/mcoles/fourrulesfornulls.asp

http://www.sqlservercentral.com/columnists/mcoles/2829.asp

In one of the first articles I wrote for SQL Server Central, I talked about SQL NULLs and three-valued logic (Four Rules For NULL). In this article I take it all back...

No, not really, but stay tuned as we talk about the darker side of ANSI NULLs.

The Original Four Rules

The original four rules I proposed for NULL-handling are all reproduced here in Figure 1.

Figure 1. The original "Four Rules"