code: public function dropIndex($name, $table)
      {
          if (strpos($table, '.') !== false && strpos($name, '.') === false) {
              if (strpos($table, '{{') !== false) {
                  $table = preg_replace('/\\{\\{(.*?)\\}\\}/', '\1', $table);
                  list($schema, $table) = explode('.', $table);
                  if (strpos($schema, '%') === false)
                      $name = $schema.'.'.$name;
                  else
                      $name = '{{'.$schema.'.'.$name.'}}';
              } else {
                  list($schema) = explode('.', $table);
                  $name = $schema.'.'.$name;
              }
          }
          return 'DROP INDEX ' . $this->db->quoteTableName($name);
      }
docs: Builds a SQL statement for dropping an index.
  @param string $name the name of the index to be dropped. The name will be properly quoted by the method.
  @param string $table the table whose index is to be dropped. The name will be properly quoted by the method.
  @return string the SQL statement for dropping an index.