Inserting Records and Using Debug Mode

We'll finish off creating a Hello App that says hello to our name by inserting a record into the persons table in our database, and showing the person's name on the index route.

Inserting a record

Code

@app.route('/')
def index():
  person = Person.query.first()
  return 'Hello ' + person.name

Screencast cont'd (introducing debug mode)

Takeaways

FLASK_DEBUG=true

will set debug mode to ON, which will automatically restart the server whenever we make changes to our application.

We can set this in-line with our flask run command,

$ FLASK_DEBUG=true flask run

or export it ahead of time in our terminal session on a separate line before we run the server,

$ export FLASK_DEBUG=true
$ flask run

Now we have everything we need to complete our Hello SQLAlchemy app. Now complete Exercise 4.

Starter Code for app.py

from flask import Flask
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql://udacitystudios@localhost:5432/example'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
db = SQLAlchemy(app)

class Person(db.Model):
  __tablename__ = 'persons'
  id = db.Column(db.Integer, primary_key=True)
  name = db.Column(db.String(), nullable=False)

db.create_all()

@app.route('/')
def index():
  return 'Hello World!'