text: import os
  import sys
  import traceback
  import time
  import pandas as pd
  from microsrv_interface.comm_interface import db_CONN, set_env_param #,sftp_CONN, queue_CONN
  
  def main():
      # Set Database interface
      db_interface = db_CONN()
  
      # Get frequency of app container
      frq = int(set_env_param('FREQUENCY_SEC','30'))
      # Get Application name
      app_name = set_env_param('APP_NAME',str(os.uname()[1]))
  
      try:
          # Connect to Database
          print(' [*] Connecting to database')
          with db_interface as db_conn:
              print(' [+] Connected to database')
  
              # col = ['ID','val']
              # qStr = 'SELECT [ID],[val] FROM [telemDataStore].[dbo].[test_tbl]'
              # df = db_interface.select_query(qStr,col)
  
              # dummy df
              d = {'ID': [1, 2], 'val': ['Test-30', 'Test-40']}
              df = pd.DataFrame(data=d)
              # Set dataframe property
              db_interface.set_df(df,'[telemDataStore].[dbo].[test_tbl]')
              # Select top 10 records
              sel_df = db_interface.select_db_table(10)
              print(sel_df)
              print()
              # Sub-select to avoid identity field
              db_interface.set_subselect_cols(['val'])
              sel_df = db_interface.select_db_table(10)
              print(sel_df)
              print()
  
              # Write dataframe to linked database table
              row_cnt = db_interface.insert_dataframe()
              print(row_cnt)
              print()
              sel_df = db_interface.select_db_table(10)
              print(sel_df)
  
              print(df)
          time.sleep(frq)
      except Exception as err:
          print()
          print("An error occurred while executing main proc.")
          print(str(err))
          traceback.print_tb(err.__traceback__)
      return
  
  if __name__ == '__main__':
      try:
          main()
      except KeyboardInterrupt:
          print('Interrupted')
          try:
              sys.exit(0)
          except SystemExit:
              os._exit(0)