Re: [dotNetRDF-Develop] Building SPARQL programmatically

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Yes I think I actually like that approach better

I did say it was a rough cut, send me a pull request if you make a start
on it otherwise I'll get to it when I get to it

Might be nice to have that as our major new feature for 0.8.0 since I plan
on getting 0.7.2 out Wednesday time allowing

Rob

On 9/24/12 1:32 PM, "Tomasz Pluskiewicz" <tom...@gm...>
wrote:

>Hi Rob
>
>The QueryBuilder starts very promising. Way better than the Algebra API.
>
>However I'm not convinced with the extension methods way. What I could
>suggest is a specialized builder class which holds the query inside
>and the user can retrieve it whenever he is done with building.
>Something along the below:
>
>public class QueryBuilder : IQueryBuilder
>{
>  private SparqlQuery _query = new SparqlQuery();
>
>  // such constructor only as a suggestion
>  // could also create factory methods for the query types
>  public QueryBuilder(SparqlQueryType queryType)
>  {
>     _query.QueryType = queryType;
>  }
>
>  // Now all methods are simmilar but not extension
>  // and will return self. For example:
>  public IQueryBuilder Where(IEnumerable<Triple> ts)
>  {
>    foreach (Triple t in ts)
>    {
>      _query = _query.Where(t.Subject, t.Predicate, t.Object);
>    }
>   return this;
>  }
>
>  public SparqlQuery GetExecutableQuery()
>  {
>    // not sure the Copy() is required
>    // the internal API forbids any changes to the underlying query anyway
>    // but shall that change any time, it could lead to unexpected results
>    return _query.Copy();
>  }
>}
>
>I'm suggesting this, because currently the SparqlQuery has quite a few
>public getters and methods and at first it was very obscure what
>functionality the QueryBuilder actually provides.
>
>Also notice the IQueryBuilder interface. I think it would be
>beneficial to let the users actuall mock the builder and have the
>calls verified in unit tests. Last but not least, there could be not
>one but multiple interfaces implemented by the QueryBuilder class,
>which gives us power to order some of the calls if we ever need such a
>feature.
>
>It's already 10:30PM here so I won't be reworking the code today.
>Tomorrow maybe, depending on your thoughts on all this :).
>
>Tom
>
>On Mon, Sep 24, 2012 at 7:20 PM, Rob Vesse <rv...@do...> wrote:
>> Off the top of my head it should look something like this, assuming you
>> create the URIs as INode instances first:
>>
>> ISparqlAlgebra algebra = new Select(
>>   new Filter(
>>    new Join(
>>     new LeftJoin(
>>      new LeftJoin(
>>       new BGP(),
>>       new BGP(new TriplePattern(new VariablePattern("?item"), new
>> NodeMatchPattern(rdfType), new NodeMatchPattern(someClass)))
>>      ),
>>      new BGP(new TriplePattern(new VariablePattern("?item"), new
>> NodeMatchPattern(rdfType), new NodeMatchPattern(someOtherClass)))
>>     ),
>>     new BGP(new TriplePattern(new VariablePattern("?item"), new
>> NodeMatchPattern(foafName), new VariablePattern("?itemName")))
>>    ),
>>    new UnaryExpressionFilter(new LangMatchesFunction(new
>>LangFunction(new
>> VariableTerm("itemName")), new ConstantTerm(en)))
>>   ),
>>   new String[] { "item" });
>>
>> Not the prettiest thing to build, see the QueryBuilder class [1] on the
>> fluent-query [2] branch for an initial rough cut of a more user friendly
>> fluent style API, see the unit tests in that commit for some examples of
>> building queries
>>
>> Hopefully that style of API will be much more readable than the above
>>and
>> much more user friendly
>>
>> Rob
>>
>> [1]
>> 
>>https://bitbucket.org/dotnetrdf/dotnetrdf/changeset/f0654d04f2612d6e215ff
>>17
>> d166ba99c74e781af
>> [2]
>> 
>>https://bitbucket.org/dotnetrdf/dotnetrdf/changesets/tip/branch(%22fluent
>>-q
>> uery%22)
>>
>>
>> On 9/24/12 5:40 AM, "Tomasz Pluskiewicz" <tom...@gm...>
>> wrote:
>>
>>>Hello again
>>>
>>>I tried to build some algebra programmatically but I failed miserably :)
>>>
>>>Could you please as an example help me with expressing the below
>>>SPARQL in Algebra API?
>>>
>>>SELECT ?item
>>>{
>>>  OPTIONAL { ?item a  ex:someClass . }
>>>  OPTIONAL { ?item a  ex:someOtherClass . }
>>>  ?item foaf:name ?itemName
>>>  FILTER( langMatches( lang(?itemName), "en" ))
>>>}
>>>
>>>This should give me enough insight to get up to speed with the API.
>>>
>>>Thanks,
>>>Tom
>>>
>>>On Sat, Sep 22, 2012 at 7:02 PM, Tomasz Pluskiewicz
>>><tom...@gm...> wrote:
>>>> Also are there any introductory examples on creating SPARQL Algebra.
>>>> It could be the way to go for my initially. Are there many scenarios
>>>> when it would be impossible to convert it to a query?
>>>>
>>>> Tom
>>>>
>>>> On Sat, Sep 22, 2012 at 11:30 AM, Tomasz Pluskiewicz
>>>> <tom...@gm...> wrote:
>>>>> Thanks Rob
>>>>>
>>>>> I could look into it. Please point me int the right direction in the
>>>>> code where the internal API is located.
>>>>>
>>>>> Tom
>>>>>
>>>>> On Fri, Sep 21, 2012 at 10:26 PM, Rob Vesse <rv...@do...>
>>>>>wrote:
>>>>>> Hey Tom
>>>>>>
>>>>>> Right now it's somewhat limited, you can build the algebra
>>>>>> programmatically and try and convert it back to a query with the
>>>>>>AsQuery()
>>>>>> method but that isn't guaranteed to work (some algebras can't be
>>>>>>converted
>>>>>> back into queries).  Otherwise you have to generate a string and
>>>>>>then
>>>>>> parse it.
>>>>>>
>>>>>> Most of the SparqlQuery API is protected internal/private, I have a
>>>>>>To Do
>>>>>> item to add a public fluent style API for building queries that I
>>>>>>will
>>>>>> likely do for the next release if that helps.  I/you can start
>>>>>>building
>>>>>> that out in a feature branch if that would solve your issue?
>>>>>>
>>>>>> Rob
>>>>>>
>>>>>> On 9/21/12 11:39 AM, "Tomasz Pluskiewicz"
>>>>>><tom...@gm...>
>>>>>> wrote:
>>>>>>
>>>>>>>Hi
>>>>>>>
>>>>>>>Please tell me what are the options for building SPARQL
>>>>>>>programatically with dotNetRDF? Is there any such API?
>>>>>>>
>>>>>>>Regards,
>>>>>>>Tom
>>>>>>>
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