title: Does Entity Framework save all, or only save changes?
body: <p>If I have code that updates an entry, and the update only changes two columns with the rest remaining the same after inputting data for maybe ten columns, does it save all ten columns or only the two that change?</p>
  
  <p>If I update 10 columns but nothing changes in each one, does it bother doing the update?</p>
  
  <p>Example</p>
  
  <pre><code>col1 | col2 | col3
  -----|------|-----
  1    |2     |3
  </code></pre>
  
  <p>Update col1 to 1, col2 to 2, and col3 to 4. Does is save all three or only col3 since it was the only one that changed?</p>
  
  <p>If I update col1 to 1, col2 to 2, and col3 to 3, nothing changed so does it update still?</p>
  
  <p>On that note, how can I see the SQL generated by SaveChanges?</p>