Re: contrasing SPARQL Federation + DM/R2RML vs. SQL federation tools

On Mon, Feb 13, 2012 at 12:01 PM, Eric Prud'hommeaux <eric@w3.org> wrote:

> * Juan Sequeda <juanfederico@gmail.com> [2012-02-13 10:19-0600]
> > Eric,
> >
> > In SQL Server, there is a feature called Distributed Query that can join
> > heterogeneous data sources, including joining Oracle data and a text file
> > in a single SQL Server query.
> >
> > http://msdn.microsoft.com/en-us/library/ms188721.aspx
>
> That gave me a bit of marketecture, but do you know how to use the system?
> I can imagine a couple ways it could work:
>
> 1. Configuration maps schema names to remote database endpoints. User
> queries join tables with explicit schema names to connect disparate
> databases.
>


Exactly. I haven't used it. But from what I hear, you can query the remote
table by

select * from remoteserver.remotedb.remoteschema.remotetable

SQL Server has a defined mapping of their types with other types. If I
understand correctly, you either bring in the table into you local sql
server, or you can also push parts of the query to the remote database, and
they can translate sql server sql to other sql dialects.



>
> 2. User queries are expressed in an SQL-like language with extra
> productions to target joins against particular databases.
>
>
Not that I'm aware of.


> 3. Configuration created a virtual warehouse in a single schema. User
> queries against this warehouse/view are re-written to connect to the remote
> database.
>

This is just the general ETL data warehouse data integration approach,
right :)


>
>
> > I'm giving the Linked Data tutorial at semtech. If our tutorials don't
> > overlap, I could help you out with this.
>
> Excellent -- tx.
>
>
Don't quote me on any of this ;) I could get confirmation and we could work
this out together.


>
> > Juan Sequeda
> > +1-575-SEQ-UEDA
> > www.juansequeda.com
> >
> >
> > On Mon, Feb 13, 2012 at 10:13 AM, Eric Prud'hommeaux <eric@w3.org>
> wrote:
> >
> > > I'm giving a talk at SemTech which I'm lead to believe will cover
> SPARQL
> > > over SQL databases. One of the motivators for the SemWeb is that we
> get to
> > > connect everything to everything, including e.g. sets of SQL DBs. The
> > > relational world has some tooling for the latter case, e.g. "Oracle
> > > Database Streams" and "SQL Server Integration Services". What do y'all
> know
> > > about them? It could help some audience members if I were able to
> contrast
> > > existing SQL tooling against SPARQL over DB-backed RDF graphs.
> > >
> > > --
> > > -ericP
> > >
> > >
>
> --
> -ericP
>