/**
  * Return the UPDATE clause ready for inserting into a query.
  *
  * @param SQLExpression $query The expression object to build from
  * @param array $parameters Out parameter for the resulting query parameters
  * @return string Completed from part of statement
  */
 public function buildUpdateFragment(SQLUpdate $query, array &$parameters)
 {
     $table = $query->getTable();
     $text = "UPDATE {$table}";
     // Join SET components together, considering parameters
     $parts = array();
     foreach ($query->getAssignments() as $column => $assignment) {
         // Assigment is a single item array, expand with a loop here
         foreach ($assignment as $assignmentSQL => $assignmentParameters) {
             $parts[] = "{$column} = {$assignmentSQL}";
             $parameters = array_merge($parameters, $assignmentParameters);
             break;
         }
     }
     $nl = $this->getSeparator();
     $text .= "{$nl}SET " . implode(', ', $parts);
     return $text;
 }