为 cx_Oracle 动态使用 INSERT - Python

Question

I've been looking around so hopefully someone here can assist:

I'm attempting to use cx_Oracle in python to interface with a database; my task is to insert data from an excel file to an empty (but existing) table.

I have the excel file with almost all of the same column names as the columns in the database's table, so I essentially want to check if the columns share the same name; and if so, I insert that column from the excel (dataframe --pandas) file to the table in Oracle.

import pandas as pd
import numpy as np
import cx_Oracle

df = pd.read_excel("employee_info.xlsx")

con = None
try:
    con = cx_Oracle.connect (
          config.username,
          config.password,
          config.dsn,
          encoding = config.encoding)
except cx_Oracle.Error as error:
      print(error)
finally:
       cursor = con.cursor()
       rows = [tuple(x) for x in df.values]
       cursor.executemany( ''' INSERT INTO ODS.EMPLOYEES({x} VALUES {rows})   '''

I'm not sure what sql I should put or if there's a way I can use a for-loop to iterate through the columns but my main issue stems from how can I dynamically add these for when our dataset grows in columns?

I check the columns that match by using:

sql = "SELECT * FROM ODS.EMPLOYEES"
cursor.execute(sql)
data = cursor.fetchall()
col_names = []
for i in range (0, len(cursor.description)):
    col_names.append(cursor.description[i][0])

a = np.intersect1d(df.columns, col_names)
print("common columns:", a)

that gives me a list of all the common columns; so I'm not sure? I've renamed the columns in my excel file to match the columns in the database's table but my issue is that how can I match these in a dynamic/automated way so I can continue to add to my datasets without worrying about changing the code.

Bonus : I also am importing SQL in a case statement to create a new column where I'm rolling up a few other columns; if there's a way to add this to the first part of my SQL or if it's advisable to do all manipulations before using an insert statement that'll be helpful to know as well.

Answer 1

Look at https://github.com/oracle/python-oracledb/blob/main/samples/load_csv.py

You would replace the CSV reading bit with parsing your data frame. You need to construct a SQL statement similar to the one used in that example:

sql = "insert into LoadCsvTab (id, name) values (:1, :2)"

For each spreadsheet column that you decide matches a table column, construct the (id, name) bit of the statement and add another id to the bind section (:1, :2) .