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On 9/13/13 9:33 AM, Michael Brunnbauer
wrote:
Hello Kingsley,
On Fri, Sep 13, 2013 at 08:37:01AM -0400, Kingsley Idehen wrote:
I agree wholeheartedly. RDF and SPARQL make data integration easier
(without
solving the fundamental issues of course).
What is the fundamental issue, as you see it?
http://en.wikipedia.org/wiki/Heterogeneous_database_system#Problems_of_heterogeneous_database_integration
## In Turtle, for sake of clarity re, my world-view ##
<http://en.wikipedia.org/wiki/Heterogeneous_database_system#Problems_of_heterogeneous_database_integration>
<#myLabel> "Data-de-silo-fication" ;
<#sameAs> <#HeterogeneousDataFederation>,
<#DataVirtualization>, <#DataSpaces>,
<#MasterDataManagement> ;
<#comment> """This problem covers data disparity issues that
include: shape, location, and relation semantics (or lack
thereof)""" .
## Turtle End ##
So I assume we are in agreement re., the problem?
http://lists.w3.org/Archives/Public/public-lod/2013Jun/0458.html
I see the fundamental issue (or pain point) being data-de-silo-fication.
RDF is nice for Extract Transform Load. The problems start if you want to
change data.
Change sensitivity is handled via the use of Linked Data Views over
disparate data sources. This is what R2RML facilitates albeit rarely
mentioned, sadly.
Views can be transient, materialized, or a configurable mix of both.
That's certainly the case re. Virtuoso i.e., make a change in its
SQL DBMS (or a remote ODBC or JDBC accessible DBMS) and they are
reflected in all your SPARQL queries and Linked Data URI lookups.
The same even applies to RESTful or SOA services that are attached
to Virtuoso (we cover 100+ protocols and formats).
We have Replication (Snapshot and Transactional) and HTTP
(including cache invalidation) baked into Virtuoso.
But they are a bad option for data
storage because maintaining consistency is so difficult (think about
deleting
a row or transactions).
I don't know what that really means.
Suppose you have an App with user registration. If you store the user data
in a triple store, deleting a user with SPARQL becomes difficult.
That doesn't apply to every triplestore. That doesn't apply to
Virtuoso. We even have large customer running OLTP like workflows
with something like 40 million named graphs. BTW -- as part of the
workflow, Virtuoso has to factor in deltas such that it doesn't
perform wholesale named graph deletions etc.
Removing
a single triple is not enough. Storing the user in a named graph may help but
probably creates other problems and definitely makes querying a lot more
complicated.
What about SPARQL transactions ? Starting a transaction, reading and updating,
commiting the transaction.
We are a full blown ACID DBMS. See our benchmark reports. These
simply aren't new issues since we have a hybrid DBMS.
Is there a triple store that supports this with
all the fidelity of modern RDB systems ?
Yes. It's called Virtuoso !
I say that because we simply don't have that problem in our hybrid DBMS.
I don't know what that really means. Can I modify data with SPARQL *and* SQL
in your DBMS ? If yes, how does that work ?
Of course you can. We support SPARQL 1.1 Update. We are SQL-99
compliant. We do ACID. We have serious customers doing OLTP like
stuff using RDF or SQL aspects of Virtuoso. [1][2][3][4]
Links:
1. http://bit.ly/ZOCmaD -- shows we even have the performance
difference between SPARQL and SQL down to insignificant levels via
Star Schema Benchmark Report
2. http://bit.ly/10pvAbF -- blog post about this effort
3. http://bit.ly/Yf5etP -- Berlin SPARQL Benchmark Report (note:
this particular benchmark is SQL relational DBMS oriented)
4. http://bit.ly/14ULX2F -- 150 Billion triples scale report
5. http://bit.ly/RtdGjA -- CoRelational DBMS Concepts post that
includes live links to R2RML Views built atop SQL data
6. http://bit.ly/13fnIbr -- example of R2RML views atop an Oracle
DBMS hooked into Virtuoso via ODBC .
Kingsley
Regards,
Michael Brunnbauer
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--
Regards,
Kingsley Idehen
Founder & CEO
OpenLink Software
Company Web: http://www.openlinksw.com
Personal Weblog: http://www.openlinksw.com/blog/~kidehen
Twitter/Identi.ca handle: @kidehen
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