title: From and From Named Graph in SPARQL
body: <p>I am getting a confusion related to <code>FROM</code> and <code>FROM NAMED</code> graphs in SPARQL. I did read the specifications relating to these two construct in the <a href="https://www.w3.org/TR/2013/REC-sparql11-query-20130321/#specifyingDataset" rel="nofollow noreferrer">SPARQL Specifications</a>. I just want to confirm my understanding. </p>
  
  <p>Suppose an RDF Dataset is located at IRI <code>I</code>. <code>I</code> is made up of:</p>
  
  <ul>
  <li>a default graph <code>G</code> </li>
  <li>3 named graphs <code>{(I1,G1), (I2,G2), (I3,G3)}</code></li>
  </ul>
  
  <p>Now, suppose I have a SPARQL query:</p>
  
  <pre><code>SELECT * 
  FROM I
  FROM I1
  FROM NAMED I2
  </code></pre>
  
  <p>So if I understand, to evaluate this query, the SPARQL service may construct the active graph at the back, this active merge will contain:</p>
  
  <ul>
  <li>a default graph which is the merge of <code>I</code> and <code>I1</code></li>
  <li>a named graph <code>I2</code></li>
  </ul>
  
  <p>Is this understanding right?</p>