My postgresql database does not respond to python commands

Question

I am applying SQL commands with Python (PyCharm), and for some reason that I can't understand the following method can't be executed:

def save_to_db(self):
    connection = psycopg2.connect(user='postgres', password='valid', database='learning', host='localhost')
    with connection.cursor() as cursor:
        cursor.execute('INSERT INTO users (email, first_name, last_name) VALUES (%s, %s, %s)',(self.email, self.first_name, self.last_name))
    print('here save_to_db')    # as a trace
    connection.commit()
    connection.close()

It is called from the following script:

from user import User    # the class where the methods are
my_user = User('email@email.com', 'first name', 'last name', None)  # in the database there is auto-increment for the primary key (4th argument)
my_user.save_to_db()

Neither the database is updated, nor the print command I use as a trace is giving any outcome in the run window of pycharm. Even if I use a non valid password, instead of an error I get "Process finished with exit code 0". However that method worked once, the first time I applied it, allowing me to save some data in the database. Since then I get response from the database only through pgadmin4. I would be glad if I could get some help about this issue. Thank you in advance.

There may be some more details in the previous thread I raised for the same issue: python-postgresql, seems to be connected but no respond

EDIT: I'm placing the full code of the application. The file with the User class is following:

import psycopg2


class User:
def __init__(self, email, first_name, last_name, id):
    self.email = email
    self.first_name = first_name
    self.last_name = last_name
    self.id = id

def __repr__(self):
    return "<User {}>".format(self.email)

def save_to_db(self):
    with psycopg2.connect(user='postgres', password='valid', database='learning', host='localhost')
        with connection.cursor() as cursor:
            cursor.execute('INSERT INTO users (email, first_name, last_name) VALUES (%s, %s, %s)', (self.email, self.first_name, self.last_name))
    print('here save_to_db')    # as a trace to define wether or not the method is executed


@classmethod
def load_from_db_by_email(cls, email):
    with psycopg2.connect(user='postgres', password='valid', database='learning', host='localhost') as connection:
        with connection.cursor() as cursor:
            cursor.execute('SELECT * FROM users WHERE email=%s', (email,))
            user_data = cursor.fetchone()
            return cls(user_data[1], user_data[2], user_data[3], user_data[0])

And here is following the file which is calling both of the two methods.

from user import User

saveToDb = 1 # 1 to save, else to load

if saveToDb==2:
    print('save')    # a print method again as a trace
    my_user = User('email@email.com', 'first_name', 'last_name', None)
    my_user.save_to_db()
else:
    print('load')    # a print method again as a trace
    my_user = User.load_from_db_by_email('email@email.com')
    print(my_user)

Again I'm using a print method as a trace, and what it comes is that also the code that's calling the methods is not executed.

Answer 1

It looks like an exception is being generated and you are not seeing it. Or some code that is wrapping this function is catching it with except: and not reporting it.

How about this varient:

EDIT: Added a couple of print()s.

def save_to_db(self):
    print("DEBUG: ENTER save_to_db()");
    rc = False
    my_database = 'learning'
    try:
        connection = psycopg2.connect(user='postgres', password='zSvG3$', database=my_database, host='localhost')
    except Exception as e:
        print("Unable to connect to [" + my_database + "] - " + str(e))
        connection = None

    if (connection != None):
        cursor = connection.cursor()
        try:
            cursor.execute('INSERT INTO users (email, first_name, last_name) VALUES (%s, %s, %s)',  (self.email, self.first_name, self.last_name))
            connection.commit()
            connection.close()
            rc = True
        except Exception as e:
            print("INSERT FAILED - "+str(e))
    print("DEBUG: EXIT save_to_db()");
    return rc