Re: Test cases for BINARY columns

Hi Richard

Thanks for your suggestions/comments, please read my comments inline

On Mar 1, 2012, at 3:48 PM, Richard Cyganiak wrote:

> Boris,
> 
> Database D016-1table1primarykey10columns3rowsSQLdatatypes contains a column declared as BINARY(20).
> 
> BINARY(20) is a fixed-length binary type, so shorter values get padded (with zero-value bytes IIRC) upon insertion.
> 
> The DM test case that exercises this database contains xsd:hex64binary encoded versions of the original, non-padded data.
> 
> This is incorrect, it should contain the padded version.
> 
> Perhaps more reasonably, the column declaration should be changed to VARBINARY(20).

I updated the sql script.

> 
> This is similar to the issue we had earlier with CHAR/VARCHAR.
> 
> Note: It seems there's no test case for R2RML that uses a binary type. Please add one. The easiest thing is to just use a binary column in a column-valued object map with rr:column and without a rr:datatype declaration. When rr:datatype is *not* specified, then R2RML always uses the natural datatype mapping, hence the result will be the same hex64binary typed literal as in the DM.
> 
> Note: Juan requested weird corner cases, so here's one that's actually kind of cool. Let's use a VARBINARY column in a URI template to create data URIs [1]:
> 
> rr:template "data:image/png;base64,{\"Photo\"}";
> 
> This should produce something like this:
> 
> data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg==
> 
> If everything works, you can actually open that URI in your browser (it produces a small round red dot).

If I understood you correctly, we should have sth like [1], so for the predicateObjectMap we would have

 rr:predicateObjectMap
    [ 
      rr:predicate ex:photo;
      rr:objectMap [ rr:template "data:image/png;base64,{\"Photo\"}"; ];
    ];

    .
so, the resultant object would be an IRI ?
<data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO9TXL0Y4OHwAAAABJRU5ErkJggg==>

If this is the case, I'm not sure if we can parse that as URI 

Best

Boris

[1] http://www.w3.org/2001/sw/rdb2rdf/test-cases/#R2RMLTC0016e 


> 
> Best,
> Richard
> 
> [1] http://en.wikipedia.org/wiki/Data_URI_scheme