--- a/paq/prov-aq.html Fri Jan 04 13:26:13 2013 +0000
+++ b/paq/prov-aq.html Fri Jan 04 14:23:43 2013 +0000
@@ -625,10 +625,10 @@
The general procedure for using a provenance query service is:
</p>
<ol>
- <li>Retrieve the service description.</li>
- <li>Within the service description, locate information about a recognized query mechanism. Any unrecognized descriptions should be ignored.</li>
- <li>If a recognized query mechanism is described, extract information needed to use that mechanism (e.g. a URI template or a SPARQL service endpoint URI)</li>
- <li>Use the information obtained to query for required provenance</li>
+ <li>retrieve the service description;</li>
+ <li>within the service description, locate information about a recognized query mechanism, ignoring unrecognized descriptions;</li>
+ <li>if a recognized query mechanism is described, extract information needed to use that mechanism (e.g. a URI template or a SPARQL service endpoint URI); and</li>
+ <li>use the information obtained to query for required provenance.</li>
</ol>
<p>
The patterns for using provenance query services are designed around REST principles [[REST]], which aim to minimize coupling between client and server implementation details.
@@ -903,7 +903,7 @@
</tr>
<tr style="vertical-align: top;">
<td><code>DirectQueryService</code></td>
- <td>Type for a direct HTTP query service. Mainly for use in RDF provenance query service descriptions, to distinguish direct HTTP query service descriptiuons from other query service descriptions.</td>
+ <td>Type for a direct HTTP query service description. Mainly for use in RDF provenance query service descriptions, to distinguish direct HTTP query service descriptions from other query service descriptions.</td>
<td><a href="#direct-http-query-service" class="sectionRef"></a></td>
</tr>
<tr style="vertical-align: top;">
@@ -933,6 +933,14 @@
<td><a href="#forward-provenance" class="sectionRef"></a></td>
</tr>
</table>
+ <p class="note">
+ It is tempting to think of <code>prov:DirectQueryService</code> as a particular kind of <code>prov:ProvenanceQueryService</code>, but they are, in practice, distinct resources.
+ <br/>
+ <br/>
+ This is seen when one considers that a <code>prov:ProvenanceQueryService</code> may have multiple query mechanisms associated with it (e.g. a <code>prov:DirectQueryService</code> <em>and</em> an <code>sd:Service</code>). Also, they serve quite different purposes in the process of using provenance query services: look for <code>prov:ProvenanceQueryService</code> to discover query services of any kind, then for associated <code>prov:DirectQueryService</code> or <code>sd:Service</code> resources to get details of specific mechanisms to use to access the service.
+ </p>
+
+
</section>
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