I don’t really KNOW relational databases. I’ve hung around with them quite a bit but I have no real experience. I know there are things I don’t understand about them. As with anything I’m genuinely uncertain about, I don’t even know what it is I don’t understand. I am in unknown unknowns territory.
While getting my Umbrello UML modelling tool working again, I tripped over this:
It was a bit of a surprise because:
a) entity-relationship diagrams aren’t part of UML and
b) the explanation of the ‘overlapping specialisation’ example didn’t make sense to me.
I now knew this was one of the things I didn’t understand, but the KDE document wasn’t helping me. I searched for a better explanation and it took me here:
It uses UML class diagrams to model relations. I think this might sort me out.
I used to be an operating system specialist. I’m not any more. I want to use a computer as a tool to get something done, like most people do.
I’ve used Linux for many years without ever learning too much about it. There was a time when I considered that to be proof it had caught up with Windows for ease-of-use. Windows has crashed and burned on me more than once
Things seemed to change when Canonical took their premature decision to move Ubuntu to the Unity graphical shell on the Gnome desktop. I finally lost patience with Unity a few months ago and installed the Gnome Desktop instead. It’s been mostly OK but I’ve had a couple of odd disappearances of freemind (Java) and umbrello (KDE.) Umbrello is running with it’s icons missing and I’ve manually reinstalled freemind. I now have to work out how to add a Java app to the Gnome desktop. This is too hard for ‘us normal people’.
In the meantime, freemind is started from my terminal with the command
sh -c “cd ~/bin/freemind && sh ‘freemind.sh'”
At least that’s nice and simple, if you like that kind of thing. Sadly, I don’t.
Update: I’ve fixed Umbrello. Via the KDE bug system I discovered that Fedora users were short of an icon library so I experimentally searched for the same library in the Ubuntu repos and added it. The oxygen-icon-theme transitional package adds oxygen5-icon-theme.
I’ve updated the bug report:
Update 2: It came unfixed the first time I tried to save – after a couple of hours work, obviously. I’ve backed up to paper before applying this workaround:
I used the synaptic package manager to add kio then let it sort itself out. UML updates saved, with no loss of data. This is why I use a real operating system. Morning not wasted after all. The Linux love is returning.