How to write pandas dataframe to oracle database using to_sql?

Question

I'm a new oracle learner. I'm trying to write a pandas dataframe into an oracle table. After I have made research online, I found the code itself is very simple, but I don't know why my code doesn't work.

I have read the pandas dataframe from my local file:

import cx_Oracle
import pandas as pd
import os

dir_path = os.path.dirname(os.path.realpath("__file__"))
df = pd.read_csv(dir_path+"/sample.csv")

Now print df, the dataframe df shold be like this:

   DATE            YEAR     MONTH      SOURCE      DESTINATION
0  11/1/2017 1:00  2017     1          AL          CO  
1  11/2/2017 1:00  2017     5          GA          ID  
2  11/3/2017 1:00  2017     12         GA          MO    

Then I create connection with the database by using cx_Oracle, it works. Next I try to write the dataframe df into the table TEST. This table TEST is an empty table which already exist in oracle database, it has columns including DATE, YEAR, MONTH, SOURCE, DESTINATION in oracle. All the datatype matches the df sample data. My code is as follows:

conn_str = u'account/password@host:1521/server'
conn = cx_Oracle.connect(conn_str)

# Write records stored in a DataFrame to a oracle database
df.to_sql('TEST', conn, if_exists='replace') # the error shows here

conn.close()

It shows error:

DatabaseError: Execution failed on sql 'SELECT name FROM sqlite_master WHERE type='table' AND name=?;': ORA-01036: illegal variable name/number

How to solve the problem? Thank you very much for your time!

Answer 1

I've seen similar questions on SO - it happens when you try to write to Oracle DB using connection object created by cx_Oracle.

Try to create connection using SQL Alchemy:

import cx_Oracle
from sqlalchemy import types, create_engine

conn = create_engine('oracle+cx_oracle://scott:tiger@host:1521/?service_name=hr')

df.to_sql('TEST', conn, if_exists='replace')