Error:
[oracle@a01oragridqa01 python]$ python test_load.py
   1   'sami'
0  2   'john'
1  3   'mary'
2  4  'peter'
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 3 entries, 0 to 2
Data columns (total 2 columns):
 #   Column  Non-Null Count  Dtype
---  ------  --------------  -----
 0   1       3 non-null      int64
 1   'sami'  3 non-null      object
dtypes: int64(1), object(1)
memory usage: 176.0+ bytes
Traceback (most recent call last):
  File "/usr/local/lib64/python3.6/site-packages/sqlalchemy/engine/base.py", line 1780, in _execute_context
    cursor, statement, parameters, context
  File "/usr/local/lib64/python3.6/site-packages/sqlalchemy/dialects/oracle/cx_oracle.py", line 1347, in do_executemany
    cursor.executemany(statement, parameters)
cx_Oracle.DatabaseError: ORA-00904: "'sami'": invalid identifier

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "test_load.py", line 28, in <module>
    df.to_sql('test', engine, index=False, if_exists='append')
  File "/usr/local/lib64/python3.6/site-packages/pandas/core/generic.py", line 2615, in to_sql
    method=method,
  File "/usr/local/lib64/python3.6/site-packages/pandas/io/sql.py", line 598, in to_sql
    method=method,
  File "/usr/local/lib64/python3.6/site-packages/pandas/io/sql.py", line 1406, in to_sql
    raise err
  File "/usr/local/lib64/python3.6/site-packages/pandas/io/sql.py", line 1398, in to_sql
    table.insert(chunksize, method=method)
  File "/usr/local/lib64/python3.6/site-packages/pandas/io/sql.py", line 830, in insert
    exec_insert(conn, keys, chunk_iter)
  File "/usr/local/lib64/python3.6/site-packages/pandas/io/sql.py", line 747, in _execute_insert
    conn.execute(self.table.insert(), data)
  File "/usr/local/lib64/python3.6/site-packages/sqlalchemy/engine/base.py", line 1286, in execute
    return meth(self, multiparams, params, _EMPTY_EXECUTION_OPTS)
  File "/usr/local/lib64/python3.6/site-packages/sqlalchemy/sql/elements.py", line 324, in _execute_on_connection
    self, multiparams, params, execution_options
  File "/usr/local/lib64/python3.6/site-packages/sqlalchemy/engine/base.py", line 1488, in _execute_clauseelement
    cache_hit=cache_hit,
  File "/usr/local/lib64/python3.6/site-packages/sqlalchemy/engine/base.py", line 1843, in _execute_context
    e, statement, parameters, cursor, context
  File "/usr/local/lib64/python3.6/site-packages/sqlalchemy/engine/base.py", line 2024, in _handle_dbapi_exception
    sqlalchemy_exception, with_traceback=exc_info[2], from_=e
  File "/usr/local/lib64/python3.6/site-packages/sqlalchemy/util/compat.py", line 207, in raise_
    raise exception
  File "/usr/local/lib64/python3.6/site-packages/sqlalchemy/engine/base.py", line 1780, in _execute_context
    cursor, statement, parameters, context
  File "/usr/local/lib64/python3.6/site-packages/sqlalchemy/dialects/oracle/cx_oracle.py", line 1347, in do_executemany
    cursor.executemany(statement, parameters)
sqlalchemy.exc.DatabaseError: (cx_Oracle.DatabaseError) ORA-00904: "'sami'": invalid identifier
[SQL: INSERT INTO test ("1", "'sami'") VALUES (:"1", :"'sami'")]
[parameters: [{'"1"': 2, '"\'sami\'"': "'john'"}, {'"1"': 3, '"\'sami\'"': "'mary'"}, {'"1"': 4, '"\'sami\'"': "'peter'"}]]
(Background on this error at: https://sqlalche.me/e/14/4xp6)
[oracle@a01oragridqa01 python]$