getluky.net

I’ve been spending a few minutes working on building a query for Pre-Ordered Tree Traversal, or PTT. The library phpGACL uses MPTT, a modified form of PTT.

This approach is really advantageous to writing procedural recursive SQL. Without getting too technical, you basically store some ordering metadata at insert time that allows you to easily query the hierarchy and return an ordered depth path to the location of the desired node.

I posted about this earlier, but I may write additional notes about the algorithm as I gain more understanding and familiarity.

Metadata? Thesauri? Taxonomies? Topic Maps!

Good overview for relatively technical audience. The primary problem i’ve had with describing these sorts of systems is that the diagrams are only understandable to someone who’s willing to go through the mental hoops to implement it.

Once a prototype gets implemented, then it’s easier to see what the application looks like. However, because it masks the complexity and richness of the underlying system, it’s crucial to include some real value propositions in terms of added features. Otherwise, the hierarchical guys will come in and offer to simply extend schemas to include the couple of extra fields to emulate the facets.

It’s kind of funny how there’s an opposition of thought between the network-map way of thought and the hierarchical way of thought.

http://blogs.msdn.com/oldnewthing/archive/2004/05/28/143771.aspx

A hilarious finance paper (Hilarious to me, anyway) that tries to model bureaucratic inefficiency and paperwork as a method for tightly documenting employee output and thus improving efficiency during managerial turnover. Includes these gems:

“Of course, selling the firm to the manager would eliminate her incentive to deviate from value-maximizing actions. To rule out this uninteresting solution to the agency problem, we assume that the manager is credit constrained. The manager has to remain as an employee of the shareholders, who must impose an incentive scheme on the manager to prevent her from distorting the firmâ™s organizational design.”

“For any given organizational choice O, the manager will try to renegotiate whenever her expected salary is below {math formula I can’t paste}, a threshold that takes into account that the Board will optimally reset the employeeâ™s compensation contract in case of managerial turnover.”