Re: new subscriber, not sure how to post my query to your list

[Michael Ross <michael e ross gmail com>]

Dear Leon,

I hope you enjoy Dia.  Sounds like drawing with it will be the least of your problems, if you are getting into db use.

I am not saying you won't get answers to your questions, but mostly your questions are about how to draw a proper chart according the the traditions for that sort of chart.  The questions that appear hear are more like: 

I think you should have designed dia to work this way and how could you have been so foolish not to have read my mind?  I demand that you get to work on it.

Why isn't this just like Visio?

And recently, a real knee slapper - why did you rip me off by charging me for your sorry program?

Or the better ones,

How do I get the Dia to print all on one page?

I have this enhancement I would like to try and code, how can we work together?.

Can I help writing the help files?

Can I add a set of shapes to the distro for Dia?

My Dia is messing up when I try to do this thing...here is an example, and my PC is this kind, and my OS it this OS. Help?

You could look at the shapes of a sheet that comes with Dia and think, "my that guy really knows how to make a @#$%^^ chart."  But, he might have been the only person here that knew how to chart in that way, everyone else likes to do it a different way, no one has used those shapes for 10 years, etc.

So it will be sort of random if anyone here knows much about tinyint, for example.

But how to draw with Dia is definitely in bounds.

I think, if I understand you correctly, the red an yellow highlights are about the snapping of objects.  Drag a zigzag line near a circle and it will show red when you are near a connection point that will grab it.  If you then move the circle the line will follow it. If you grab the line not near an end or other grip it will pull the line loose from the connections to other objects it was snapped to.  Not sure what the yellow highlighting is about off the top of my head.

Welcome, hopefully someone else knows just what you are asking about.

Mike

On Tue, Apr 24, 2012 at 6:38 PM, Leon <leonpaul2 gmail com> wrote:

Hi

Have just subscribed to your Dia-mail list, but am having trouble finding ou thow to post a help request on Dial mailing list.

Grateful if you can insert the following post for me, or advise.  Thanks

"Have not designed a db since days of Access2, so very rusty. Am now considering using 'Base' in LO/HSQLDBv2.  Am a newbie to both UML, Dia, and Base/HSQL!   I remember with Access, I created my tables, and THEN created an ERD diagram automatically from the design.    I guess logically the ERD should come first, and the table creation and links flow from that.  So as OOo/LO dont appear to be able to Create a ERD, and I saw a reference in OOo documentation recommending Dia, have been trying to use it.    I successfully used Dia .972 to draw all the Classes I need, but am a bit unsure HOW to create the correct links.

1)  My Access generated ERD's had only 1 type of link: lines between table ID's with arrow symbol at FK end, no symbol at PK end.  As I rcall, the textbooks of the day used the same symbol - often with a 1:n at the FK end.  Dia-UML has a slection of link symbols.  Should I use the UML-Generalisation tool, or the UML-Aggregation tool to create the typical 1:n & other relations ?

2)  When dragging a link towards a key in a class ( to make a relation between 2 classes) I noticed when the 'handle' reached the border of the Class, the shape turns 'red' - so I assumed it had connected (as per Dia.Manual 4.2.5).  After creating many more links, I inadvertantly dragged the 'handle' further into the Class box, and noticed the shape turns 'yellow' - no ref. in Dia.Manual

I would like an explanation of the difference between the 'Red' and 'yellow' signals, and which should I use.

3)  Once the ERD is complete, what current tools are there to a) report on its correctness, and b) use it to generate the tables and links in LO/HSQLDB-V2 ?  My platform is Windows7. I saw a quite old guide using 'tedia2SQL' to create SQL statements. However, the tedia2sql site states it no longer works as the Dia file format has changed.  Also, I think the guide used linux and it was not clear if tedia2sql worked in a simple Windows7 platform.

A minor question using Dia is:  In case I later want to Edit the name or type of a field (used in many Classes) is it safe to save the .dia uncompressed, then use 'Notepad' to do a global 'Replace' ?

I am also very much a newbie with SQL.  For some very small lookup tables I would like to use a 'tinyint' as an auto-incrementing id for new entries.  All examples seem to use 'Int'.  Any reason I can't use tinyint ?

I apologise for asking such basic questions and will be very grateful if you can help me through this initial phase with using Dia for front-ending a Database design."

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Michael E. Ross

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