[Python] ORA-01036 error on executemany() oracledb in Python UPDATE query

During the execution of method executemany() the error "ORA-01036: illegal variable name/number arises". Execution of a similar method execute() with the same data is successful.

Сode that ends with an error:

update_data_df = read_docs_df[['CONTRACT_NUM', 'DOCID']].copy()
cur_upd = conn_dwh.cursor()
dataUpdate = [tuple(i) for i in update_data_df.values]
print(dataUpdate)
sqlTxt = "UPDATE USERBOX_MIDDLE_OFFICE.rvp_doc_partner_to_archive SET DOCID = :2 WHERE CONTRACT_NUM = ':1'"
cur_upd.executemany(sqlTxt, dataUpdate)
updated_docs = cur_upd.rowcount
conn_dwh.commit()
cur_upd.close()


DatabaseError: ORA-01036: illegal variable name/number

print(dataUpdate) output: [('П/0097232-Д8', 7481640), ('П/0117840-Д2', 7131468), ('1/А-БПИ/Нск-Д1', 6819213), ('П/0082021-Д5', 7425529)]

Code worked successfully:

update_data_df = read_docs_df[['CONTRACT_NUM', 'DOCID']].copy()
cur_upd = conn_dwh.cursor()
updated_docs = 0
for row in update_data_df.itertuples():
sqlTxt = f"UPDATE USERBOX_MIDDLE_OFFICE.rvp_doc_partner_to_archive SET DOCID = {row.DOCID} WHERE CONTRACT_NUM = '{row.CONTRACT_NUM}'"
print(sqlTxt)
cur_upd.execute(sqlTxt)
updated_docs += cur_upd.rowcount
conn_dwh.commit()
cur_upd.close()


Python 3.9 oracledb 1.4.1

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