SVG, autodia and SQL ( was various bits of digest, Vol 1 #801)

[Aaron Trevena <tj droogs org>]

On Sun, 30 Mar 2003 dia-list-request@gnome.org wrote:
> > I have to point out that I like the Dia XML as it is. After all compare
> > the abundance of tols for creating and parsing it against those for
> > argouml or kivio.
>
> Well there are other factors, argouml is java based and kivio is not
> entirely free which is distasteful to some.

oh, yes, also their formats are pretty grim.

T take back what I said about it being impossible to extract useful
information from argouml's XMI, it is in fact just very very very hard and
fraustrating.

> What worries me is IBMs Eclipse and their XMI based EMF diagrams.
> Now that IBM has bought Rational Rose, these standards are sure to become
> even more important.
> http://www.eclipse.org/emf/
> http://www.rational.com/products/rose/

XMI is horrid and nasty, sorry to go on, but XMI seems to be a fig leaf
for badly designed XML required by Java programmers embedding who embed
their application and presentation logic in XML and make a fugly mess that
only very expensive and massively-overengineered tools can process.

> > I thought it would be relatively easy to convert to/from Dia and Argouml,
> > given they both use XML to represent UML Class diagrams - its the same
> > information, the structures can't be that different, right? wrong!
>
> "converting from one XML to another XML must be easy"
> is only slighly less ludicrous than saying
> "converting from one ASCII based file format to another"
> especially if you have ever looked at any of the XML produced by MSWord or
> Visio.

XML should make it easy to extract relevent information, particularly if
two different format refer to the same kind of thing. All the
meta-information should make it easy to find say, a class or
generalisation, in some XML representing a UML Class Diagram - I should be
so lucky.

> You mean besides an Entity Relationship (ER) diagram?
> I am sure if you are willing to do some work on Dia people will point you
> in the right direction as to how best to do it.

Sorry I don't use E-R diagrams, I (and pretty much every programmer I know
who deals with database schemas) uses a variation of the class diagram.

> > "converting from one XML to another XML must be easy"
> > is only slighly less ludicrous than saying
> > "converting from one ASCII based file format to another"
> > especially if you have ever looked at any of the XML produced by MSWord or
> > Visio.
> libxstl is realy great at doing this.  XSTL is specificly made for
> converting XML to XML and along with formatting objects can be used to
> do things like XML to PDF or any number of formats.  Quite a good tool
> and standard.

yucky! why would I use XSLT when I could get the job done in a fraction of
the time using perl and XPATH or XML::Simple ?

The problem isn't transforming from one format to another - its finding
the information you want. The nasty n-deep mess of certain XML/XMI formats
would be EVEN MORE deeply unpleasent to deal with using XSLT.

> If I have a database, say SQL Server, and I want to get the whole set of
> about 40 tables into Dia, is Autodia the tool that does this for me? Or
> do I need to find the script that says "create table x..." and have
> Autodia parse that?

It is now - I just released version 1.6 which will take either SQL or a
DBI DSN and slurp out the information, it recognises some of the SQL
Server types (I have been trying to forget that monstrosity since I don't
have to deal with its hissy fiots and unhelpfulness anymore), but you can
easily add any extra types to the list in the Autodia::Handler:SQL module.

> This is the kind of thing (I think) J.K. Lowden is interested in:
> End-to-end Database1-->GenericRepresentation-->Database2. It is also, as
> it turns out, something I've recently become very interested in since I
> need to migrate from an MS SQL Server to PostgreSQL sometime in the near
> future. Out of this conversion I would like to get a nice Dia-contained
> ERD as well.

indeed, for my next trick I will add dia to SQL support to autodia and
possibly even dia to DBI which would just magically create your database
for you. I already read in dia files so this shouldn't be hard - I haven't
gone in this direction yet for fear of treading on other peoples toes, but
it can probably be justified now as more people would find autodia useful
if it could do everything both ways (i.e. perl to dia to perl and dbi to
dia to sql, etc)

regards,

A.

-- 
Aaron J Trevena - Perl Hacker, Kung Fu Geek, Internet Consultant
AutoDia --- Automatic UML and HTML Specifications from Perl, C++
and Any Datasource with a Handler.     http://droogs.org/autodia