[Uml-devel] request for enlightment
wallus at results-hannover.de
Mon Feb 16 03:53:09 UTC 2004
BARTKO, Zoltan wrote:
> 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)
> 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...
I'm using singelton, like a pool. I have to different kinds,
one which creates a one primary key (last number+1), and
one which store link information for a given key from another table (1:1).
(1:many) you can use a (1:1), in which the second one contains a Map.
Sorry no more time, I have to get ready something (very hard). But I'm
Dr. Harald Wallus
Am Listholze 78, D-30177 Hannover
Tel: +49(0)511 90951-23 Fax: +49(0)511 90951-90
Email: wallus at results-hannover.de
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