Python, Flask + SQLAlchemy - query not working

Question

I've got the following Python code

app = Flask(__name__)      
app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql+psycopg2://my_user_name:@localhost:5432/my_db'
db = SQLAlchemy(app)

@app.route("/submit_signup_email", methods=["POST"])
def submit_signup_email():
  email = request.form["email"]
  created_timestamp = int(time.time())
  signup            = Signup(email, created_timestamp)
  db.session.add(signup)
  db.session.commit()

  # not working...
  test = Signup.query.filter_by(email=email).first()

Which works fine and I can check that a row has been inserted correctly in my DB.

But if I run this code after "db.session.commit()".....

test = Signup.query.filter_by(email=email).first()

I get the following error.

OperationalError: (OperationalError) could not connect to server: No such file or directory Is the server running locally and accepting connections on Unix domain socket "/var/pgsql_socket/.s.PGSQL.5432"?

I'm not sure what the problem is, my Signup model looks like this in "models.py"

from flask_sqlalchemy import SQLAlchemy
from app import app, db

class Signup(db.Model):
  __tablename__     = "signups"
  id                = db.Column(db.Integer, primary_key=True)
  email             = db.Column(db.String)
  created_timestamp = db.Column(db.Integer)

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

  def __repr__(self):
    return self.email

How did you connect the DB? Did you connect it before the query? — waitingkuo, Jun 04 '13 at 07:33
"db" is defined in the same file. It's already there, isn't it? — ericbae, Jun 04 '13 at 07:41
Try to put the query right after commit, and see whether it works or not. — waitingkuo, Jun 04 '13 at 07:42
That's exactly what I did actually. I've edited my post to reflect this. — ericbae, Jun 04 '13 at 07:44
let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/31170/discussion-between-waitingkuo-and-ericbae) — waitingkuo, Jun 04 '13 at 08:05

Ying.Zhao · Answer 1 · 2013-06-04T08:29:01.390

0

db = SQLAlchemy()
db.init_app(app)
db.app = app

init_app(app) :
This callback can be used to initialize an application for the use with this database setup. Never use a database in the context of an application not initialized that way or connections will leak.

and "from app import app,db" is incorrect

edited Jun 04 '13 at 08:29

answered Jun 04 '13 at 08:11

Ying.Zhao

154
3
13

score -1 · Answer 2 · edited Jun 20 '20 at 09:12

-1

Seems like a PostfreSql Problem, ref. Maybe you should try to restart your server.

EDIT

After seeing your code (in the chat room), the problem might be "Circular Import". Try to prevent that

edited Jun 20 '20 at 09:12

Community

1
1

answered Jun 04 '13 at 08:00

waitingkuo

89,478
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Python, Flask + SQLAlchemy - query not working

2 Answers2

EDIT