Rick Hillegas wrote:
Hi Samuel,
I agree with Dag that this issue is a little complicated and you may
want to tackle something smaller first just to get familiar with the
Derby codeline. The objects stored in system tables, which Dag
mentioned, are a special kind of user defined type with a highly
optimized storage representation. A good place to start is to grep the
codeline for UserDefinedType. This will introduce you to a lot of
compiler support for user types.
I think that the storage support for Java serializable types is pretty
much complete, the big part of this project will be adding the DDL (SQL
standard part 13) and the testing.
The system columns are only special in that they implement an internal
interface for writing themselves to disk. If they only implemented
java.io.Serializable or java.io.Externalizable then they would be
written by the store using those interfaces. I believe for the rest of
the code they are just handled as a generic Java type.
Dan.
