title: Should I call SaveChanges once or after each change?
body: <p>I need to make several changes in my database in my controller.</p>
  <pre><code>foreach (var valueStream in model.ListValueStream)
  {
      ValueStreamProduct vsp = new ValueStreamProduct(valueStream.Id, product.Id);
      db.ValueStreamProduct.Add(vsp);
  }
  db.SaveChanges();
  </code></pre>
  <p>Should I call SaveChanges at the end or each time I make changes?</p>