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POQuerying Project Gutenberg catalog.rdf via SPARQL
 

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  1. POQuerying Project Gutenberg catalog.rdf via SPARQL
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    <p>I'm having difficulty structuring a SPARQL query for the Project Gutenberg catalog (available at <a href="http://www.gutenberg.org/wiki/Gutenberg:Feeds" rel="nofollow noreferrer">Gutenberg Feeds</a> toward the bottom of the page). I know it is a fundamental lack of understanding on my part of how SparQL/RDF/etc. actually work, conflating it with SQL, etc. But I've tried several tutorials, and I just can't quite get my mind around piecing the WHERE clause together with what seems to be the multidimensional dataset.</p> <p>I have imported catalog.rdf into a TDB database (from the Jena project), and am using the tdbquery tool to set up my query initially, before I wrap it into a command-line tool that allows searching by author or title.</p> <p>Here is what I have so far:</p> <pre><code>$ cat gutenquery.tq PREFIX rdf: &lt;http://www.w3.org/1999/02/22-rdf-syntax-ns#&gt; PREFIX rdfs: &lt;http://www.w3.org/2000/01/rdf-schema#&gt; PREFIX dc: &lt;http://purl.org/dc/elements/1.1/&gt; PREFIX dcterms: &lt;http://purl.org/dc/terms/&gt; PREFIX dcmitype: &lt;http://purl.org/dc/dcmitype/&gt; PREFIX cc: &lt;http://web.resource.org/cc/&gt; PREFIX pgterms: &lt;http://www.gutenberg.org/rdfterms/&gt; PREFIX dcmitype: &lt;http://purl.org/dc/dcmitype/&gt; SELECT ?title ?author WHERE { ?book dc:title ?title ; dc:creator ?author } LIMIT 10 $ ./tdbquery --loc=/var/db/gutenberg/ --file=gutenquery.tq ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- | title | author | ====================================================================================================================================================================== | "The Belgian Curtain\nEurope after Communism"^^rdf:XMLLiteral | "Vaknin, Samuel, 1961-"^^rdf:XMLLiteral | | "Fairy Tales; Their Origin and Meaning\nWith Some Account of Dwellers in Fairyland"^^rdf:XMLLiteral | "Bunce, John Thackray, 1828-1899"^^rdf:XMLLiteral | | "The World English Bible (WEB): Zephaniah"^^rdf:XMLLiteral | "Anonymous"^^rdf:XMLLiteral | | "Lectures of Col. R. G. Ingersoll - Latest"^^rdf:XMLLiteral | "Ingersoll, Robert Green, 1833-1899"^^rdf:XMLLiteral | | "Selections from Erasmus\nPrincipally from his Epistles"^^rdf:XMLLiteral | "Erasmus, Desiderius, 1469-1536"^^rdf:XMLLiteral | | "East and West\nPoems"^^rdf:XMLLiteral | "Harte, Bret, 1836-1902"^^rdf:XMLLiteral | | "The Enormous Room"^^rdf:XMLLiteral | "Cummings, E. E. (Edward Estlin), 1894-1962"^^rdf:XMLLiteral | | "The Enormous Room"^^rdf:XMLLiteral | _:b0 | | "Actes et Paroles, Volume 4\nDepuis l'Exil 1876-1885"^^rdf:XMLLiteral | "Hugo, Victor, 1802-1885"^^rdf:XMLLiteral | | "L'ÃŽle Des Pingouins"^^rdf:XMLLiteral | "France, Anatole, 1844-1924"^^rdf:XMLLiteral | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------- </code></pre> <p>A typical entry from PG looks like this, although not all fields are present in all records:</p> <pre><code>&lt;pgterms:etext rdf:ID="etext7250"&gt; &lt;dc:publisher&gt;&amp;pg;&lt;/dc:publisher&gt; &lt;dc:title rdf:parseType="Literal"&gt;A Connecticut Yankee in King Arthur's Court, Part 9.&lt;/dc:title&gt; &lt;dc:creator rdf:parseType="Literal"&gt;Twain, Mark, 1835-1910&lt;/dc:creator&gt; &lt;pgterms:friendlytitle rdf:parseType="Literal"&gt;A Connecticut Yankee in King Arthur's Court, Part &lt;/pgterms:friendlytitle&gt; &lt;dc:language&gt;&lt;dcterms:ISO639-2&gt;&lt;rdf:value&gt;en&lt;/rdf:value&gt;&lt;/dcterms:ISO639-2&gt;&lt;/dc:language&gt; &lt;dc:subject&gt; &lt;rdf:Bag&gt; &lt;rdf:li&gt;&lt;dcterms:LCSH&gt;&lt;rdf:value&gt;Americans -- Great Britain -- Fiction&lt;/rdf:value&gt;&lt;/dcterms:LCSH&gt;&lt;/rdf:li&gt; &lt;rdf:li&gt;&lt;dcterms:LCSH&gt;&lt;rdf:value&gt;Arthurian romances -- Adaptations&lt;/rdf:value&gt;&lt;/dcterms:LCSH&gt;&lt;/rdf:li&gt; &lt;rdf:li&gt;&lt;dcterms:LCSH&gt;&lt;rdf:value&gt;Britons -- Fiction&lt;/rdf:value&gt;&lt;/dcterms:LCSH&gt;&lt;/rdf:li&gt; &lt;rdf:li&gt;&lt;dcterms:LCSH&gt;&lt;rdf:value&gt;Fantasy fiction&lt;/rdf:value&gt;&lt;/dcterms:LCSH&gt;&lt;/rdf:li&gt; &lt;rdf:li&gt;&lt;dcterms:LCSH&gt;&lt;rdf:value&gt;Kings and rulers -- Fiction&lt;/rdf:value&gt;&lt;/dcterms:LCSH&gt;&lt;/rdf:li&gt; &lt;rdf:li&gt;&lt;dcterms:LCSH&gt;&lt;rdf:value&gt;Knights and knighthood -- Fiction&lt;/rdf:value&gt;&lt;/dcterms:LCSH&gt;&lt;/rdf:li&gt; &lt;rdf:li&gt;&lt;dcterms:LCSH&gt;&lt;rdf:value&gt;Satire&lt;/rdf:value&gt;&lt;/dcterms:LCSH&gt;&lt;/rdf:li&gt; &lt;rdf:li&gt;&lt;dcterms:LCSH&gt;&lt;rdf:value&gt;Time travel -- Fiction&lt;/rdf:value&gt;&lt;/dcterms:LCSH&gt;&lt;/rdf:li&gt; &lt;/rdf:Bag&gt; &lt;/dc:subject&gt; &lt;dc:subject&gt;&lt;dcterms:LCC&gt;&lt;rdf:value&gt;PS&lt;/rdf:value&gt;&lt;/dcterms:LCC&gt;&lt;/dc:subject&gt; &lt;dc:created&gt;&lt;dcterms:W3CDTF&gt;&lt;rdf:value&gt;2004-07-07&lt;/rdf:value&gt;&lt;/dcterms:W3CDTF&gt;&lt;/dc:created&gt; &lt;dc:rights rdf:resource="&amp;lic;" /&gt; </code></pre> <p></p> <p>In addition to, e.g. dc:author and dc:title, I'd like to get the value from the attribute of pgterms:etext rdf:ID="STUFF IN HERE":</p> <pre><code>&lt;pgterms:etext rdf:ID="etext7250"&gt; </code></pre> <p>As well as combining the entries in the list under dc:subject, etc. Basically, provide all the info on this book as a single coherent entry via the command-line query.</p> <p>So, my questions:</p> <ol> <li>How can I combine the attribute value from pg:eterms rdf:ID with the rest of the query?</li> <li>How can I combine the entries under dc:subject's list into one string?</li> <li>Since not all fields show up for every record, should I use the OPTIONAL() clause to surround fields that don't always appear?</li> <li>How can I limit my query based on a user-specified string? Am I supposed to use FILTER() for that?</li> </ol> <p>Thank you so much. I have been able to construct queries to get single-layer information, but anything beyond that, attributes etc. are nigh inscrutable to me. This is much different to standard SQL, and a much more involved project than I thought at first.</p>
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