[RFC/gdl2] Postgres Adaptor

[David Ayers]

Hello,

I've been testing with PostgreSQL 7.2.3 lately.  But our 
"Postegres95Adaptor" currently relies on features introduced with 7.3, 
like the CASCADE in the DROP TABLE statement in the schema generation 
and the structure of the pg_tabels system table.  I've locally added a 
version ivar to Postegres95AdaptorChannel, and runs a SELECT VERSION() 
upon openChannel, parses the output to retrieve the version so that the 
channel cen support server version specific implementations.

Yet in other places like Postgres95SQLExpression  
+dropTableStatementForEntityGroup: it seems kind of over kill to try to 
connect to the database with the modelGroup's model's 
connectionDictionary, just to find out whether we  need the CASCADE or 
whether we have to omit it, but it seems necessary.

I was flirting with the idea of only supporting the 7.3 version, but as 
many GNU/Linus distros are still shipping with 7.2 this seems like a bad 
idea.

I'd like to know what other people think.  Should we start adding 
runtime checks on the Server version?  (We can't rely on configury as 
the Client API is independent of these server features, but we might 
have to take that into account also)

If so which Versions should we "officially" support?

Cheers,
David