Re: Data Cartridges

The data cartridge thing seems to be only loosely defined by Oracle at this point. I got some info after extensive digging at Openworld recently. Oracle8 supports pl/sql callouts to external 'c' programs. It does this via a listener connection to a thing called 'extproc'. You create a 'librarary' object in pl/sql - a new concept for O8 - which references the shared library external thing, which started by extproc when first referenced by a session. This much you can surmise from the Oralce8 docs.

What they also mention in the docs is that the 'c' program is part of the callers session and can make callbacks into Oracle. That is what makes it a data cart. Two way access between pl/sql and something external. Oracle is developing some docs to explain all this and to describe the rules. yes, there are rules.

For instance, the 'c' program will run in its own process space, to protect Oracle from your bad 'c' code. Plus, the external thing cannot commit your session. It can, however, start its own session back into Oracle. There will also be an api to get to some of Oracles internla goodies, for handling special indexes and the like, hopefully transparently.

The thing is, data carts. are just not quite ready yet. But, read about extproc and you can figure most of it out.

Roger Snowden Received on Tue Nov 11 1997 - 00:00:00 CET