/**
  * {@inheritDoc}
  */
 public function constraintSql(Table $table, $name)
 {
     $data = $table->constraint($name);
     $out = 'CONSTRAINT ' . $this->_driver->quoteIdentifier($name);
     if ($data['type'] === Table::CONSTRAINT_PRIMARY) {
         $out = 'PRIMARY KEY';
     }
     if ($data['type'] === Table::CONSTRAINT_UNIQUE) {
         $out .= ' UNIQUE';
     }
     return $this->_keySql($out, $data);
 }