On Tue, 25 Jul 2006 09:37:42 +0200 (Romance Daylight Time) Michael Van Canneyt <[EMAIL PROTECTED]> wrote:
> > > On Tue, 25 Jul 2006, Mattias Gaertner wrote: > > > On Tue, 25 Jul 2006 10:59:54 +0700 > > Bisma Jayadi <[EMAIL PROTECTED]> wrote: > > > >> Hi all... > >> > >> Currently I'm planning to develop an application for database modeling, in > > my > >> spare time. I plan it'd be similar to FabForce's DBDesigner 4 > >> (http://www.fabforce.net/dbdesigner), though it has nothing to do with the > > > >> FabForce's. Yes, I'll reinvent the wheel, but I have good reasons for it. > >> > >> Current development status is I've finish the class for table model which > > is > >> derived from TCustomListBox with custom paint method. And now I'm starting > > to > >> develop the relation model. The first idea came to my mind was create a > > new > >> class contains 3 TBevel(s) which are combined to build a relation model. > > After > >> few hours of coding, I found this idea is too complicated (I've to > > synchronize 3 > >> objects) so I plan to solve it another way. > >> > >> Here I need some suggestions... which is the best component I should > > derive from > >> to make the relation model? I've been thinking about TPaintBox but I think > > it > >> too big and too complex for just a relation model component. I want it > > able to > >> paint fast and requires less memory. > > > > How fast and how much less memory? > > If your tables only contains a few hundred entries and there are no more > > than a few dozens tables, then the listboxes are ok. > > Otherwise, you can use instead of TCustomListBox a TCustomControl. This has > > less overhead, but you have to implement the items and scrolling yourself. > > (TCustomControl has a scrollbar, but you have to paint the offset). > > The connections should be painted. > > > > When your relation control works nice, we could use it for an UML modeller > > for the IDE. > > I wouldn't recommend this approach. I tried various database modellers, > and the only workable one for large databases was one which painted the > objects all from scratch. Right. 250 components are far too many childs for a single parent. OTOH, 250 tables is too much for most people. ;) > Although I would be among the first to use an UML and Database modeller in Lazarus :-) If we would have a nice control, we could start it. Mattias _________________________________________________________________ To unsubscribe: mail [EMAIL PROTECTED] with "unsubscribe" as the Subject archives at http://www.lazarus.freepascal.org/mailarchives
