I have read many answers to this same question, but haven't seen anything that works for me.
I have a very basic app just to test things (in app.py and database.py). I'm using ElephantSQL, psycopg2-binary and have checked - the table on ElephantSQL is made from this code, but cannot insert from here. I can obviously insert from ElephantSQL.
I am just testing with the headline string, but headline will ultimately be the result of a web scrape using bs4.
This is my first time using a database with Python, but I'm absolutely blocked on what should be quite simple code. Please help.
This is database.py:
from psycopg2.extras import execute_values
CREATE_HEADLINES = """CREATE TABLE IF NOT EXISTS headlines
(headline TEXT);"""
INSERT_HEADLINE = "INSERT INTO headlines (headline) VALUES %s;"
SELECT_ALL_HEADLINES = "SELECT * FROM headlines;"
def create_tables(connection):
with connection:
with connection.cursor() as cursor:
cursor.execute(CREATE_HEADLINES)
def create_headlines(connection):
with connection:
with connection.cursor() as cursor:
cursor.execute(CREATE_HEADLINES)
def add_headline(connection, headline):
with connection:
with connection.cursor() as cursor:
cursor.execute(INSERT_HEADLINE, (headline))
def get_headlines(connection):
with connection:
with connection.cursor() as cursor:
cursor.execute(SELECT_ALL_HEADLINES)
return cursor.fetchall()
this is the main part of my app.py (I've hidden sensitive stuff):
import psycopg2
from bs4 import BeautifulSoup
import database
connection = psycopg2.connect(db_url)
headline = 'Hello, world!'
print(headline)
print(type(headline))
database.create_tables(connection)
database.create_headlines(connection)
database.add_headline(connection, headline)
Returns this error:
Hello, world!
<class 'str'>
Traceback (most recent call last):
File "/Users/jamesdanielmalvern/femicide/scraper/app.py", line 33, in <module>
database.add_headline(connection, headline)
File "/Users/jamesdanielmalvern/femicide/scraper/database.py", line 21, in add_headline
cursor.execute(INSERT_HEADLINE, (headline))
TypeError: not all arguments converted during string formatting
CodePudding user response:
An INSERT
needs around the values parenthesis, that is also true for placejholders
INSERT_HEADLINE = "INSERT INTO headlines (headline) VALUES (%s);
And You need also two elents in a list when you insert, if you have only 1 you need to add and empty one
cursor.execute(INSERT_HEADLINE, (headline,))