code: def createIndices(self):
          
  
          sql = '''CREATE INDEX name_index
                   ON Expression (name)'''
          self._cursor.execute(sql)
          self._dbConn.commit()
  
          sql = '''CREATE INDEX expression_index
                   ON Expression (expression)'''
          self._cursor.execute(sql)
          self._dbConn.commit()
docs: Index columns that are queried. The expression index can
          take a long time.