Yesterday (Wednesday) I finished off the complexity report and sent it off to Will. I then moved into looking at SQL for the remainder of the day, which I’m aiming to complete today. Yesterday I looked at Data Definition Language (DDL; used to create tables) and Data Manipulation Language (DML; used to insert data into tables), to create some tables with data into play with. I then started to look into SQL itself, and did the basics yesterday afternoon.
Today I’ve spent the morning looking at more complex SQL, namely starting to join tables. This afternoon I’m going to look at more complex joins, before then hopefully reinstalling Java3D and getting that to work — fingers crossed!
SQL update 13:07: Now I’m following an old Oracle 7 tutorial I found, but I’m completely lost on the inner and outer joins section. As such, I’m going to follow a tutorial I found on the ‘net here in a bid to finish off the SQL bit for now.
SQL update 15:16: I think I’ve now done enough SQL for the time being: I’ve been looking at reasonably complex join tutorials, which seem to be a little OTT for the time being. Need to wander off to do a couple of chores, but when I get back, it’ll be time to try and get Java3D running again! (FYI The Wikipedia page on joins explains the basics well: link)
Now on to Java … As of today, I’ve installed Java JDK 6u1 in a bid to sort things out — I may have really screwed up Eclipse, but I’ll come back to this …. I’ve also added the new environmental variable JAVA_HOME, but still no joy yet. Gone to try a hello_world program to see if it’ll work.
Right: some success — maybe!! From this page I need to add in the following info:
java -classpath . helloworld
To tell Java that the classpath is the local directory (apparently). As an aside, I’d be interested why I have to do this.
Aha — as of 17:31 Thursday 5th April 2007, we have it running again !!!! Currently tracing my buffer history to pick out anything of use … :
- cd into c:\Java\Flocking>java -classpath . Flocking3D
- don’t think this worked
- set the classpath for the JDK
- tried the java -classpath trick above on a HelloWorld app
- I then compliled everything in the directory — this could be a clue!
- then it worked!!
Okay, I’ve exited out the command prompt I had, and gone back in: needlesss to say the simulation doesn’t work now. So what do I need to do it to work again?:
- trying the java -classpath . Flocking3D => works
- I’ve echoed the classpath — no reference to the JDK. If the JDK is then set, and flocking 3D batch file run => nothing, standard NoClassDefFoundError message.
- then tried step 1/ again — this worked
- Trying flocking3d batch file on it’w own => no joy
So then … I must admit not too sure what’s going on, but it now seems I can at least get the thing working. A restart will be interesting. However, I now need to work out how to get Eclipse working again ?!
Sorted Eclipse: go into Window > Preferences. Go down to Java and select Compiler. In the JDK Compliance section, change the Compiler compliance level to 5.0 — code now compiles. A restart of Eclipse later and even the Boids code seems to have settled down … but for how long … ;-)
Now off to Prague for the w/e for PharmToxJon’s Stag do, and I should be back (in some state) on Tuesday. The next stage will be to get the 3D bird simulation to start producing data, and to start seeing what happens when the data is changed. I need to get the for loop sorted out as well, but should hopefully be a few hours work — touch wood!
