Re: [HACKERS] Regarding GSoc Application

On 04/09/2012 01:25 PM, Atri Sharma wrote:
> On Mon, Apr 9, 2012 at 10:15 PM, Andrew Dunstan<andrew@dunslane.net>  wrote:
>>
>> On 04/09/2012 12:14 PM, Dave Cramer wrote:
>>>
>>> So I'm confused, once they link a file to an FDW can't you just read
>>> it with an normal select ?
>>>
>>> What additional functionality will this provide ?
>>>
>>
>>
>> I'm confused about what you're confused about. Surely this won't be linking
>> files to an FDW, but foreign DBMS tables, in anything you can access via
>> JDBC. All you'll need on the postgres side is the relevant JDBC driver, so
>> you'd have instant access via standard select queries to anything you can
>> get a JDBC driver to talk to. That seems to me something worth having.
>>
>> I imagine it would look rather like this:
>>
>>    CREATE FOREIGN DATA WRAPPER foodb HANDLER pljava_jdbc_handler
>>    OPTIONS (driver 'jdbc.foodb.org');
>>    CREATE SERVER myfoodb FOREIGN DATA WRAPPER foodb OPTIONS(host
>>    '1.2.3.4', user 'foouser', password 'foopw');
>>    CREATE FOREIGN TABLE footbl (id int, data text) SERVER myfoodb;
>>    SELECT * from footbl;
>>
>>
>> cheers
>>
>> andrew
> Hi Andrew,
>
> Thanks for going through my proposal and commenting on it.
>
> I think you have hit the nail on the head.We will be connecting the
> foreign DBMS tables.The main aim of the project is to wrap JDBC so we
> can connect to anything that can be reached through a JDBC URL.
>
> I am considering two paths for doing this:
> The first one takes the help of the SPI(Server Programming Interface)
> and the second one directly connects through Pl/Java and JNI(Java
> Native Interface).
>

I'd say forget SPI - I don't think it's going to help you here. Just
concentrate on getting the functionality via a PL/Java wrapper. I
wouldn't worry too much about jdbc style URLs either, since logically I
think you'd want to specify the connection parameters via server and FDW
options as in my example above - that way it would be consistent with
other FDWs. But that's a piece of bikeshedding for now. Basically, you
want to implement the handler function to start with.

cheers

andrew