Since Xia, as he's known to his friends, is a rather skilled draftsman with considerable training in military intelligence evaluation, he easily found a job as an analytical tracer with Black Arts, Ltd. Now, a year later, my friend needs our help. Here's why ...

In addition to extensive aerial and satellite photo work for industry, Black Arts does a lot of analysis for the super secret National Security Agency. Hence all its employees are carefully graded by clearance for various classes of access. Naturally Xia, as a recent immigrant, was not immediately granted clearance to work on NSA projects but he was nonetheless very happy to have an excellent job where he was able to demonstrate his considerable skill at technical tracing and photo retouching.

As the scion of a wealthy and prominent family in Scmolyong, Xia was well connected with its local consular officials. He also had brought a considerable sum of family savings with him, which he invested in a small dry cleaning business employing eleven other recent immigrants from Scmolyong and neighboring Argenolio. These factors, plus a significant contribution to the Democratic National Committee in the last election cycle, enabled Xia to accelerate the generally protracted naturalization process. Within nine months he obtained his U.S. citizenship.

Overjoyed with his newly established status, Xia let on to a few close friends, including myself, that he was planning to use the uninvested portion of his savings for a lifelong ambition of immense personal importance: a sex-change operation! This he shortly did, with complete success and a speedy recovery.

On returning to work after three weeks medical leave, Xia requested that the Human Resources department of Black Arts update their personnel records to reflect his, er, her proper name. It seems that the familiar usage of "Xia" means "little prince" in Scmolyongese and that, of course, had become inappropriate. Xia decided to take the more formal name "Xant", which is without gender connotation.

Over the next couple of months, as post surgical hormone treatments began to take effect, Xant lost considerable weight. Since she had also decided to dye her hair an inconspicuous purplish-orange hue in place of the natural strong red-blond tones of native born Scmolyonese, Xant applied for a replacement driver's license. The Department of Motor Vehicles was so flustered by the changes in her personal particulars that they eventually cancelled the original license and issued a completely new one.

Meanwhile, Xant's superb sketching and colorations of aerial photos had drawn very favorable notice at work. She was promoted to rendering artist and simultaneously cleared to process NSA satellite imagery. Xant was assigned to a new desk on the "stage", as the high security image platform is called. Her work is so admired that a small crowed will frequently gather to watch one of her interpretive renderings unfold.

Xant tells me than just this week a serious complication has cropped up. Apparently NSA is performing a security audit covering the last two years. Access to NSA materials by Black Arts personnel requires not only security clearance in advance but also positive identification on each work occasion. Such identification is made through personal recognition of the subject worker by at least two other cleared workers who can match gender, height, and weight to identification documents.

The MIS director of Black Arts told the HR department that they would not be able to comply with the NSA audit because Xant's extraordinary circumstances could not be captured in Black Art's HR system. Xant, fearful of loosing her NSA clearance, and knowing my close ties to a community of expert ORM modelers, pleaded for my help in adequately capturing the needed information.

The question with which I'm now wrestling seems as if it should be rather simple. After all, it's only a matter of time: How many tables will Black Arts, Ltd. need to determine all the facts satisfying the NSA audit, including whether the artist formerly known as prince was actually a woman during his stage performances?

Terry Halpin teaches us that if the fact is variable over time, we should attach some appropriate date object type to the key of the object of focus. Makes perfect sense but I am concerned about the propagation of tables to capture all these facts through time. Furthermore, Black Arts' MIS manager is pushing me for a solution which will map to no more than two tables. How about only one table? Can you help?