code: func (m *DbMap) DropTables() error {
  	var err error
  	for i := range m.tables {
  		table := m.tables[i]
  		_, e := m.Exec(fmt.Sprintf("drop table %s;", m.Dialect.QuoteField(table.TableName)))
  		if e != nil {
  			err = e
  		}
  	}
  	return err
  }
docs: // DropTables iterates through TableMaps registered to this DbMap and
  // executes "drop table" statements against the database for each.