Category Archives: Thoughts on the World

I’ve been musing lately on why we in IT insist on forgetting so much valuable knowledge. I don’t know whether it’s because of our youth-obsessed culture and our focus on the newest and best, because of our tendency to prioritise on-the-job over traditional learning, or whether there’s simply too much in the “architect’s book of knowledge” (ABOK), and we all have to focus on the new to keep up.

I explore two very different examples: the value of understanding RS232 in this 3G+ world, and some recent discussions on service reliability, both of which can be resolved using some quite old knowledge…. (Read More…)

I am looking for one of my clients into how costs can be reduced, or quality increased, by increasing the extent to which testing is automated.

As a first step, I am trying to develop a comprehensive list of test automation “best practices”, grouped roughly by life-cycle (or iteration) stage. I’m trying to find practices which are broadly independent of specific methods and technologies, although obviously tool support may vary depending on the chosen technology.

This article is my first draft of such a list.

I’d welcome suggestions from my readers if you think there are any omissions (or if you substantially disagree with anything I’ve included).

Thanks

Andrew

If anyone is interested in hearing more about my views on architecture, and how agile methods apply to the work of the architect, please sign up for the 2006 Enterprise Architecture Conference in London in June.

I’m presenting a paper entitled “The Agile Architect”. This focuses on both how agile projects can have a strong architecture, and how architects can learn and benefit from agile approaches. I take a rather different approach to some recent papers with a similar title (e.g. at this week’s otherwise excellent Microsoft Architecture Insight conference), which suggest that agile projects can “do away with the architect”.

I look forwards to seeing you there.

Andrew

Almost all integration projects contain one or more transformations (sometimes called “mappings”) between two different structures holding equivalent data (for example the order tables in the database, and the order XML message). We know how to model the individual static data structures in various ways, but the most common approach is to represent each by a UML class model, and there are established conventions for how to do this for different data sources.

However, UML doesn’t help when it comes to the transformations themselves, and typically the detail has to be captured either in code, or a proprietary format. Most good integration tools provide some sort of “visual mapping tool”, where the developer drags and drops to create links between representations of the two structures, usually imported directly from their physical schemas. Here’s an example using SeeBeyond. Altova provide a good stand-alone data mapping tool called Mapforce – here’s an example showing it in use. The problem is that these tools work directly with the physical structure, and don’t export the mapping information in a reusable format, so that information is completely disconnected from the UML analysis or design models.

I have experimented with trying to represent mapping information in a UML model, but so far without much success. The best solution I’ve found so far is to use some sort of “pseudo code” (it could be OCL, pseudo-Java, pseudo-VB or anything similar). For example, we could easily annotate the model with code fragments such as:

Database.order_table.order_no = Message.Header.OrderNo

(where each element refers to a UML Package.Class.Attribute combination).

The problems are that it’s not clear where to put this annotation, most UML modelling tools won’t help generate it, and there’s no graphical representation. Ultimately, writing pseudo-code like this is probably not much better than abandoning the model and moving straight to using your integration tool.

My question is: does anybody know a better way? Has anybody found a good way of representing mapping information in UML? And if so, is there any good tool support?

If you know, please send me a message.