Type system notes

Inspired by Dibyendu I thought I would add some notes about the Derby
type system, since that's where I have been working for the last few
weeks for JSR 169. Though I wasn't motivated enough to write in XML for
Forrest, I added the information as a package.html in ipai.types
directory, so it would be picked up by the engine javadoc.

As Dibyendu pointed out, there is a lot of information in the existing
javadoc, close to the code where I think design docs should be. The java
doc can be created by exexcuting the top level ant target javadoc.

cd ${derby.source}
ant javadoc

This then creates javadoc in

${derby.source}/javadoc

The complete engine javadoc can be accessed through

${derby.source}/javadoc/engine/index.html

Hopefully at some point this javadoc can ben generated automatically and
added to the site.

Adding more package files would be a great goal for Derby, and I think
that Dibyendu's documents should be linked to from various store
package.html's.

Here is a direct link to the types' package.html, from svn.

https://svn.apache.org/viewcvs.cgi/*checkout*/incubator/derby/code/trunk/java/engine/org/apache/derby/iapi/types/package.html

Dan.