Fancy Bread

Amcom Technology is chock full of serious Coldfusion and Flex talent. Not the least of which is Jon Messer who has long contributed to the many of the popular CF lists. Jon is starting a new series on building an object oriented application with multiple MVC clients including Flex. The first installment introduces the series and describes modeling business objects. If you are interested in OO application design for Coldfusion, I highly recommend this series as a reference.

Yesterday, I asked Mark Mandel for some advice on tuning my object model for performance. Mark, being an ever-so-helpful (P)OSS author, gave me a few suggestions. Turns out that someone asked basically the same question on the transfer list today. Jaime Metcher made a couple of excellent points on choosing between queries and object composition. Paraphrasing, Jaime, when working with large data sets (the type of thing you might be tempted to use arrays of objects for), you will get better performance using a query. If you want to display a single instance of some object and the view is truly a composite, then your model should reflect that composition. Understanding this helps with choosing between onetomany or manytoone relationships for your object compositions.

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While cleaning out the office recently, I ran across a couple of textbooks I kept from my business school courses. I didn't care much for business school, but I did learn some valuable concepts. A few of which came from a course on Organizational Behaviour (OB). OB is a "management science" which can be briefly described as the study of groups in organizations. A goal of OB is to determine the best strategy to use within an organization to maximize employee performance (productivity) and, as a result, profitability. If you think of an organization with managers and employees, where each employee performs specific duties, you might find it strange to have a manager for every employee. You rarely see this in the real world, because it is grossly inefficient.

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Before we can scaffold screens for our generic admin, we'll need a data model. Below is a E/R diagram for the trivia game data model, which contains the following entities: User, Theme, Category, Game, Question, Answer and Response. This is a simple data model with several one-to-many relationships and no many-to-many relationships.

Briefly, a Game has a parent User and Theme. A Question has a parent Game and Category. An Answer has a parent Question. And a Response has a parent User, Question and Answer.

There's nothing too complex about this data model, so I'll focus on the conventions used to name the table primary and foreign key attributes. Each table has a PK named simply "Id" and each foreign key is prefaced by the parent entity name and "Id". For example, the Game entity has foreign key attributes "ThemeId" and "UserId".

To keep things simple and perhaps facilitate reporting or statistics down the line, all PKs and FKs are of type integer.

You can download the enclosed sql scripts to create the tables in either MSSQL or MySQL format. I chose to create proper FK constraints for the tables. If you prefer not to use foreign keys, feel free to remove them from the sql prior to running the scripts.

Next, we'll look at an Illudium template for generating a service, controller and Transfer Object decorator to support create, read, update and delete (CRUD) operations.

I've been using UML more often to visualize object relationships, so after reading Brian Rinaldi's recent posts on ColdSpring, Objects and Composition, I researched object composition and learned the subtle difference between Composition and Aggregation.

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