数据库不存在（psycopg2.OperationalError）

Question

my problem is the DATABASE not exist i dont know th reason

i did install FLASKALCHEMY and run these codes in CMD:

  -pip install flask-sqlAlqhemy 

        -python  
    - from app import db
    - db.create_all()
- pip install psycopg2

this error comes to me in CMD:

     File "C:\Users\hajar\OneDrive\Desktop\flaskpro\env\lib\site-packages\sqlalchemy\engine\default.py", line 493, in connect
        return self.dbapi.connect(*cargs, **cparams)
      File "C:\Users\hajar\OneDrive\Desktop\flaskpro\env\lib\site-packages\psycopg2\__init__.py", line 127, in connect
        conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
    sqlalchemy.exc.OperationalError: (psycopg2.OperationalError) FATAL:  database "hajar" does not exist
(Background on this error at: http://sqlalche.me/e/13/e3q8)

app.py:

 from flask import Flask, render_template, request, redirect,url_for
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql://postgres:jojo1437@localhost/hajar'
db = SQLAlchemy(app)

class user(db.Model):

    id = db.Column(db.Integer, primary_key=True)
    user_name = db.Column(db.String(80))
    email = db.Column(db.String(100), unique=True)

    def __init__(self, user_name, email):
        self.user_name = user_name
        self.email = email

    def __repr__(self):
        return '<User %r>' % self.user_name



@app.route('/')
def index():
    return render_template('add_user.html')


@app.route('/post_user', methods=['post'])
def post_user():
    user = user(request.form['username'], request.form['email'])
    db.session.add(user)
    db.session.commit()
    return redirect(url_for('index'))
if __name__ == "__main__":
    app.run()

please i realy stuck here ؟؟؟؟؟؟؟؟؟؟؟؟؟؟؟؟؟؟؟ :(

Answer 1

You've created your database as "hajar " with a trailing space while you are trying to connect to "hajar" , which won't work since that database does in fact not exists.

Simply remove the unnecessary space(s) in your create database query, re run your query and you should be good to go.

Very easy mistake to mis, I've made these sort of "obvious" mistakes hundreds of times.

Answer 2

Your error means that you did not create a data base.

See this tutorial - Define and Access the Database - for more information on this topic.

You can try to use flask init-db - see here .