[Uml-devel] request for enlightment

BARTKO, Zoltan bartko.zoltan at pobox.sk
Mon Feb 16 03:17:13 UTC 2004


Hello folks,

I am trying to figure out how to convert SQL (e.g. the PostgreSQL flavor) into UML. I have come to a few ideas, so the work is being done.

I have some big problems, however:

SQL has more properties of attributes than UML. With UML (referring to the state of Umbrello 1.2 and current cvs): what do I mean? in UML I have classifier scope, default value and that's all. I would need things like primary key (ok, I can simulate that with a built-in function), unique, (not) null, etc. Nikolaus Gradwohl, the first author of the SQL generator made it so that these additional fields were set in the documentation - not too clear.

An alternative implementation is to have a member function (ok, method) with the name of that field, one parameter (a string) and set the list of attributes in the default value. e.g.:
unique(attribs : string = "col1, col2, col3");
not too clear either.

The latter method adds more possible problems in the design. So a "design-checker" would be needed too...

If I put parameters in the documentation, they may be accidentally deleted. Not fair either.

There would be a solution: 

A) add wizards for SQL and use the second method (I think it is clearer, for the things are shown in the diagram)

or

B) modify Umbrello so that these additinal attributes are saved.

With option B I think we would violate the standards, though.

My next problem is foreign keys. They have plenty of attributes. So I need an association class. I know I can simulate an association class by splitting the association and inserting a class in the middle, but that's rude... So my question is:

are association classes planned to be implemented in near future? if so, how? As far as I know (but I may be wrong), associations are associations and UML objects are UML objects and they don't mess with each other... So adding this would require throwing out the engine and putting a new one in. But: would the standard allow us to do an association class so that there would be no dashed line to the association, just a class in the middle, marked as an assoc. class? If so, adding such functionality would be no big deal, I think I could manage it.

Is there anyone else out there who misses operation copying except for me? It would be really helpful (not to mention reordering)

That is all for the time being...

cheers

Zoltan



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