import oracledb
import pandas

oracledb.init_oracle_client()

con1 = oracledb.connect(user='', password='', dsn='')
with con1.cursor() as cursor:
  cursor.execute('SELECT * FROM table')
  columns = [col.name for col in cursor.description]
  rows = cursor.fetchmany(chunksize) # in my code, I have a generator function to fetch by batch
  df = pandas.DataFrame(rows, columns=columns)
  
# Transformation on the dataframe

con2 = oracledb.connect(user='', password='', dsn='')
with con2.cursor() as cursor:
  type_obj = con2.gettype("SDO_GEOMETRY")
  cursor.setinputsizes(geom=type_obj)
  insert_query = "INSERT INTO table (col1, col2, geom) VALUES (:col1, :col2, :geom)"
  cursor.executemany(insert_query, df.to_dict(orient='records'))
  con2.commit()