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From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Fri, 04 May 2012 13:23:52 +0100
Message-ID: <4FA3CA58.5080501@epimorphics.com>
To: Benjamin Nowack <bn@talis.com>
CC: public-sparql-dev@w3.org

On 04/05/12 07:33, Benjamin Nowack wrote:
> On 5/3/12 11:03 PM, Andy Seaborne wrote:
>> Injecting in the right place can be quite cheap - the query string upto
>> that point, the syntax, and the query string after that point. There is
>> only one point to put variables in.

> Our users are already struggling to write SPARQL 1.0 queries. Most query
> templates are just a single GP with an occasional FILTER and/or REGEX
> thrown in. They basically just write a query and then define which
> variables are meant to be exposed by our API as parameters. We probably
> can't ask them to inject the value placeholders themselves. The BINDINGS
> approach worked in almost all cases.

... beware filters don't work as your users may expect.

This was Aidan's and Stephen's comments



and motivated the change.

Do you want one set of values for the template in one query execution?

>> ARQ also allows for rewrite of parsed queries: a query can be rewritten
>> (either the abstract syntax tree or the SPARQL algebra) as replacing
>> specific variables by values prior to execution (this is even in the
>> public API). Discuss with your implementation of choice.

> ARQ is our implementation of choice :) If it's as simple as adding some
> parameters to the SPARQL API call (we only have HTTP access to the
> backend), we'd have a perfect solution. Will look into that, thanks for
> the hint!

It was on the list of features initially considered for work item with a 
skew towards the compilation efficiency side of parametrized queries:



It didn't make the cut.


> Cheers,
> Benji
>> Andy
Received on Friday, 4 May 2012 12:24:26 UTC

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