code: def createSchema(self):
      self.__connection.execute(
          "create table instrument ("
          "instrument_id integer primary key autoincrement"
          ", name text unique not null)"
      )
  
      self.__connection.execute(
          "create table bar ("
          "instrument_id integer references instrument (instrument_id)"
          ", frequency integer not null"
          ", timestamp integer not null"
          ", open real not null"
          ", high real not null"
          ", low real not null"
          ", close real not null"
          ", volume real not null"
          ", adj_close real"
          ", primary key (instrument_id, frequency, timestamp))"
      )
  
imports: from pyalgotrade.barfeed import dbfeed
  from pyalgotrade.barfeed import membf
  from pyalgotrade import bar
  from pyalgotrade.utils import dt
  import sqlite3
  import os
label_desc: Use image node_id 5 for calling the Database obj's underlying member method code with example usage: obj.createSchema() without return types