Tom Johnston is an independent consultant specializing in enterprise data architecture, and in relational, object-oriented and data warehouse modeling in various industries, including telecommunications, health care, banking, retailing and transportation. He can be reached at tjohnston@acm.org, and his Web site is www.MindfulData.org.

Splitting Episodes, Part 3
June 5, 2009 In this column, we correct a mistake made last time and learn something in the process

Splitting Episodes, Part 2
May 22, 2009 We continue our discussion from the Time and Time Again series of a bitemporal transaction, which results in the split of one...

Splitting Episodes
May 6, 2009 In this column, we discuss a bi-temporal transaction that results in the split of one episode into two episodes

Merging Episodes
April 13, 2009 In this column, we discuss a bi-temporal transaction which results in the merger of two episodes

Proactive Updates, Part 4
April 3, 2009 In previous columns, we completed a proactive update transaction against an open episode. This time, we complete our...

Proactive Updates, Part 3
March 10, 2009 This column continues the discussion of proactively updating closed episodes

Proactive Updates, Part 2
February 18, 2009 Preliminary discussions to proactively updating a closed episode

Proactive Updates, Part 1
February 6, 2009 How to enter an update before it becomes effective

Time and Time Again: Retroactive Updates
January 14, 2009 In this column, we extend an episode backwards in effective time

Time and Time Again: State Transformations
January 2, 2009 This column describes the development of a taxonomy of state transformations on asserted version tables.