Data models are good and they are clear, if you’re the person writing the application and devising the model. Hell, sometimes, they are not clear even then! So, imagine what happens when you get someone from the street to connect to your database and read your schema in order to understand it. No chance!
Now, this is not about some poor wardriver who doesn’t know how to read the implicit relationships between tables in your model - they had it coming! But what about your legit users, working on a particular aspect of your infrastructure or application, such as developers, DBAs etc. ? How on earth do they make sense of it all when they first start?
Yes, yes, in an ideal world everything’s properly documented, but when was the last time you saw that in a real life situation? Real IT people don’t write helpful comments when they create their tables, views, functions etc. Referential integrity? Don’t make me laugh! Most developers avoid database constraints, to keep the application portable between database systems and database error messages to a bare minimum. Integrity rules are usually enforced at the application level. From a DBA’s perspective, most enterprise-level databases are big collections of seemingly unrelated tables, with no business logic in the DB system itself.
But don’t despair! Help is at hand. Enter Schema Spy:
http://schemaspy.sourceforge.net/
You dowload the jar file, and then you run something along the lines of
java -jar schemaSpy_3.1.1.jar -t pgsql -cp /path/to/jdbc.jar \
-u user -p password -s schema \
-db dbname -host localhost:5432 \
-o output-dir
After a while, you have a look in output-dir, and the reports are really nice.
Schema Spy even deduces table relationships from field names and types. And it seems to support several different database systems, including Oracle and MySQL. Hurrah!
This is an interesting story, actually, because I had sound when I first installed Lenny about a month ago (well, without headphone jack sense) and then I went for a kernel update, which broke sound! The sound device now doesn’t even show up in the operating system, so it’s no use recompiling ALSA (which I have done, just in case). Now, Lenny has not been officially branded as a “stable” release yet, this is supposed to happen in 1-2 months, so here’s hoping one of these days I do a system update and suddenly everything works (again). But, as I said earlier, I am using this laptop as a development box, so lack of sound doesn’t really affect me. It’d be nice, however, to be able to listen to some mp3s while at work, which I do through my n800 (as a quick fix).
and adding all
# individual decorative elements in individual transparent gimp layers
# each layer will be converted to a separate png file with the same
# name as the gimp layer, size cropped to a minimum
# an appropriate html file with individual div blocks and css positioning
# will be automatically created
# KNOWN BUGS: you have to save at least once the layered file (.xcf)
# before application of this script. images are deposited in the dir
# you select but html file is deposited in the directory gimp runs in
# (this is not a problem if you cd to the directory you want before running
# gimp from the command line. in gimp 2 you may not undo the flatten
# operation after this script completes.
# DISCLAIMER: this is an old file. it works for me! please don’t flame.