Re: [Sparql4j-devel] Design issue: datasource

[Janne S. <jan...@pr...>]

>> I would like to propose the datasource for this driver to be
>>
>> jdbc:sparql4j:[http|other]://www.serveraddress.com[:port]/path/more;param1=value1 
>>
> 
> 
> Checking, I found that the syntax is formally:
> 
>   jdbc:<subprotocol>:<subname>
> 
> and very little restrictions on the subname (it can include : and /).
> 
> We can have our own subsubprotocol so:
> 
>   jdbc:sparql4j:<subsubprotocol>
> 
> and we don't need to have a fixed remainder; it can be dependent on the 
> subsubprotocol. For http, your suggestion of
> 
>   jdbc:sparql4j:http://www.serveraddress.com[:port]/path/more;param1=value1
> 
> look right.  To be clear, we have a URL for the service/model that we 
> are going to query (the URL is NOT the query to go to the SPARQL 
> server). The parameter is a parameter for the driver, not the SPARQL 
> protocol.
> 
> Hmm, - actually there is a level missing.  We need something like:
> 
>   jdbc:sparql4j:sparql
> 
> (yuk - 2 sparql's) to say:
> 
> jdbc:sparql4j
>   Get JDBC to route requests to our driver
> 
> jdbc:sparql4j:sparql
>   our driver is going to use the SPARQL protocol
> 
> jdbc:sparql4j:sparql:http://server/path
>   our driver is going to use SPARQL protocol at the named service
> 
> May be that's excessive.  An alternative is to not have sparql4j be the 
> subprotocol name and directly name the connection protocol:

I'm wondering what happens if the sparql protocol enables short names in 
the 'lang' attribute value, will the datasource effectively have to be 
something like

jdbc:sparql:http://server/queryprocessor?lang=sparql

This would mean any service description part of the protocol would need 
to be available before an application is built.

A datasource such as

jdbc:sparql:http://server/queryprocessor

would effectively have to fetch a service description before launching 
the first query in order to determine the 'lang' value. Luckily that 
value should be cacheable not having to fetch it before every single query.

Janne
-- 
Janne Saarela <janne.saarela at profium.com>
Profium, Lars Sonckin kaari 12, 02600 Espoo, Finland
Internet: http://www.profium.com