Is it possible to pull data from Heroku Postgresql? - postgresql

Question

Currently I am working on a telegram bot using Heroku and Flask to deploy it. I wanted to store some data into a database then I came across Heroku PostgreSQL. I managed to store data into it but I am having trouble retrieving these data from Heroku PostgreSQL. I have research quite a bit but couldn't find much information about the process on pulling the data. Can someone enlighten me or suggest what are the steps to retrieve/pull these data from Heroku PostgreSQL with Flask?
The Telegram Bot is basically a random food generator. I have stored a list of food into the data and wanted to pull these data and random generator whenever user trigger the bot/action.
Screenshot of the current heroku postgresql database
from os import environ
from flask import Flask, request, jsonify
from flask_sqlalchemy import SQLAlchemy
from flask_cors import CORS
from invokes import invoke_http
app = Flask(__name__)
app.config["SQLALCHEMY_DATABASE_URI"] = environ.get("DB_URL") or "postgres://database-url"
app.config["SQLALCHEMY_TRACK_MODIFICATION"] = false
db = SQLAlchemy(app)
CORS(app)
class Cusine(db.Model):
__tablename__ = "cusines"
id = db.Column(db.String(255), primary_key =True)
cusine = db.Column(db.String(255), nullable=False)
def __init__(self, id, cusine):
self.id = id
self.cusine = cusine
def getId(self):
return self.id
def getCusine(self):
return self.cusine
def json(self):
return {"id": self.id,"cusine":self.cusine}
db.create_all()
#app.route("/getAllCusine")#
def getAllCusine():
try:
all_cusine = Cusine.query.all()
cusines = []
for row in all_cusine:
cusines.append(row.cusine)
return jsonify(
{
"code": 200,
"message": cusines
}
),200
except:
return jsonify(
{
"code": 500,
"message": "error in getting all course"
}
),500
So, how can I pull the data from Heroku PostgreSQL using Flask?
Thank you in advance.

Answer 1

I have managed to extract the data from Heroku PostgreSQL.
I have changed the above code with the following.
import os
import psycopg2
DATABASE_URL = os.environ['DATABASE_URL']
def retrieveData():
try:
conn = psycopg2.connect(DATABASE_URL, sslmode='require')
cursor = conn.cursor()
cursor.execute("select * from table") #some sql statement
conn.commit()
result = cursor.fetchall()
cursor.close()
except (Exception, psycopg2.DatabaseError) as error:
print(error)
return result
It will return a list of tuple.
Remember to pip install psycopg2-binary
It is my very first time working with Heroku and PostgreSQL, which took me quite awhile to figure out. But thanks guy for teaching me how to properly use stackoverflow, appreciate it. Hopefully this can help someone out there (like me), who is new to PostgreSQL. Cheers :)