Hi James,
The real problem here is that VB.Net (or .Net itself for that matter) does not have an native String variant with a fixed (or maximum) length. You need to find some way around this to support your OR requirement, while not severely breaking the model's integrety.
You might be in a bit of a bind, depending on exactly how you want to model this. If you really need to model an OR situation in an implementation language - VB.Net in your case - you'll have to 'invent' something along the way. We'll come back to that. You might be stuck with this approach due to your mapping requirement.
If you can use EA's data modelling profile - by choosing the Table entity from the Class toolbox instead of the Class entity, and then allowing EA to present you with the Column dialog for attributes - you can gracefully handle strings with fixed or maximum lengths, but you lose the ability to work with implementation languages - you need to choose a DBMS and stick with its data types.
Here's what I'd suggest, remembering that whatever you choose to do must support your requirements...
If you can determine the target DBMS, or if one the EA DBMS definitions will work as a 'generic' language for you, then use the data modelling profile and you're home free.
If EA does not provide a suitable DBMS, you may be able to define one that covers your requirements. This would likely include a variety of common data types patterned on VB.Net (or native .Net) types, and would have fixed or bounded String lengths. You can then proceed with the data modelling profile as above.
If these don't work, or if the other requirements of the data modelling profile (using operations to define keys, how relations are defined, etc.) preclude this approach you will have to find a way to handle String lengths.
My best guess would be to use either a stereotype or a tagged value to indicate the length of the string. In the former case the stereotype would likely mark the String as fixed or bounded length, and there would still have to be a tag to show the length. The possible advantage would be that the stereotype would immediately draw attention to the fact that this was not a 'normal' String. If that is not practical you can always simply test or inspect the tagged values for something like 'length=50' or perhaps 'maxLength=50' or whatever, but you'll need to find a way of differentiating between fixed and variable String types.
Another approach would be to add a data type to EA's VB.Net definition. Or, you could create a slightly customized language based on the VB.Net definition. In either case you would extend or modify the 'given' data types to include your fixed or bounded String types.
Both the above solutions involve changes that somehow have to be carried over into your mapping transformation, which might mean a bit of script modification. There's some work here, and some careful testing and debugging, but you stand a good chance of getting the results you need and want, rather than a close approximation becuase "that's how the tool does it." With luck it will all pay off.
BTW, take a look at the EA User Group and Wiki. There's a link to the UG at the top of the Automation section of this forum, and the Wiki is easy to find via a quick search here. If you do some scripting and your organization allows it, please consider posting your approach and scripts to either or both of the above communities, so that others might benefit. Who knows, you might even get some good enhancements in response.
David
