dtypes1 = {c:types.VARCHAR(df[c].str.len().max()) for c in df.columns[df.dtypes == 'object'].tolist()}

df.to_sql('table1', conn2, if_exists='replace', dtype=dtypes1, index=false)

conn = create_engine('oracle+cx_oracle://.......')

SQL_statement = 'MERGE INTO '  + table2 + ' USING ' + table1 + ' ON (' + table1 + '.TIME = ' + table2 + '.TIME AND ' + table1 + '.ID = ' + table2 + '.ID) WHEN MATCHED THEN UPDATE SET ' + updateMsg + ' WHEN NOT MATCHED THEN INSERT (' + insertMsgB + ') VALUES (' + insertMsgA + ')'

conn.execute(SQL_statement)