Could it be possible to convert a postgresql database (including data) with SQLAlchemy to a sqlite database?
I tried the code below. It looks like that it works.
What do you think about it? Could this be an answer?
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import sqlalchemy as sa
import sqlalchemy.ext.declarative as sad
import sqlalchemy.orm as sao
import sqlalchemy.orm.session as sas
from sqlalchemy_utils import create_database
_Base = sad.declarative_base()
class Child(_Base):
__tablename__ = 'Child'
_oid = sa.Column('oid', sa.Integer, primary_key=True)
_name = sa.Column('name', sa.String)
def __init__(self, name):
self._name = name
class Parent(_Base):
__tablename__ = 'Parent'
_oid = sa.Column('oid', sa.Integer, primary_key=True)
_name = sa.Column('name', sa.String)
_child_fk = sa.Column('child', sa.Integer, sa.ForeignKey('Child.oid'))
_child = sao.relationship('Child')
def __init__(self, name):
super(Parent, self).__init__()
self._name = name
pstr = 'postgres://postgres#localhost/Family'
sstr = 'sqlite:///family.db'
pengine = sa.create_engine(pstr, echo = True)
sengine = sa.create_engine(sstr, echo = True)
def createPostgreSQL_Family():
"""Create for PostgreSQL the scheme and the data for testing."""
# create schema
create_database(pengine.url)
_Base.metadata.create_all(pengine)
psession = sao.sessionmaker(bind = pengine)()
# child
c = Child('Jim Bob')
psession.add(c)
psession.commit()
# parent
p = Parent('Mr. Doe')
p._child = c
psession.add(p)
psession.commit()
psession.close()
def convert():
# get one object from the PostgreSQL database
psession = sao.sessionmaker(bind = pengine)()
p = psession.query(Parent).first()
sas.make_transient(p)
#p._oid = None
c = psession.query(Child).first()
sas.make_transient(c)
#c._oid = None
psession.close()
# create and open the SQLite database
create_database(sengine.url)
_Base.metadata.create_all(sengine)
# add/convert the one object to the new database
ssession = sao.sessionmaker(bind = sengine)()
ssession.add(c)
ssession.add(p)
ssession.commit()
if __name__ == '__main__':
#createPostgreSQL_Family()
convert()
Related
I'm trying to learn Flask and use postgresql with it. I'm following this tutorial https://realpython.com/flask-by-example-part-2-postgres-sqlalchemy-and-alembic/, but I keep getting error.
Cannot import name 'AorticStenosis' from partially initialized module 'models' (most likely due to a circular import)
I understand the problem, but I can't figure out how to fix it. So, I started playing around and try to use the steps by step tutorial on something that I'm working on, but I still get the same problem.
Here's my attempt:
Models.py
from app import db
class AorticStenosis(db.Model):
__tablename__ = 'wvu-model'
id = db.Column(db.Integer, primary_key=True)
ip_address = db.Column(db.String())
date_created = db.Column(db.DateTime, default=datetime.utcnow)
e_prime = db.Column(db.Float())
LVMi = db.Column(db.Float())
A = db.Column(db.Float())
LAVi = db.Column(db.Float())
E_e_prime = db.Column(db.Float())
EF = db.Column(db.Float())
E = db.Column(db.Float())
E_A = db.Column(db.Float())
TRV = db.Column(db.Float())
prediction = db.Column(db.String())
def __init__(self, ip_address, e_prime, LVMi, A, E_e_prime, EF, E, E_A, TRV, prediction):
print('initialized')
self.ip_address = ip_address
self.e_prime = e_prime
self.LVMi = LVMi
self.A = A
self.LAVi = LAVi
self.E_e_prime = E_e_prime
self.EF = EF
self.E = E
self.E_A = E_A
self.TRV = TRV
self.prediction = prediction
def __repr__(self):
return '<id {}>'.format(self.id)
app.py
import os
import ast
import bcrypt
from flask import Flask, redirect, render_template, request, session, url_for
import flask_login
from flask_sqlalchemy import SQLAlchemy
from bigml.deepnet import Deepnet
from bigml.api import BigML
import pickle as pkl
import sklearn
app = Flask(__name__)
if app.config['ENV'] == 'production':
app.config.from_object('as_config.ProductionConfig')
else:
app.config.from_object("config.DevelopmentConfig")
# app.config.from_pyfile('as_config.py')
# app.config.from_object(os.environ['APP_SETTINGS'])
# app.config.from_object('as_config.DevelopmentConfig')
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
db = SQLAlchemy(app)
from models import AorticStenosis
login_key = app.config['LOGIN_KEY']
api_key = app.config['API_KEY']
model = app.config['MODEL']
api = BigML(login_key, api_key)
deepnet = Deepnet(model, api=api)
scaler = pkl.load(open("scaler.pkl", "rb"))
#app.route("/", methods=["GET", "POST"])
def home():
prediction = None
if request.method == "POST":
form_data = [
float(request.form.get("e_prime")),
float(request.form.get("LVMi")),
float(request.form.get("A")),
float(request.form.get("LAVi")),
float(request.form.get("E_e_prime")),
float(request.form.get("EF")),
float(request.form.get("E")),
float(request.form.get("E_A")),
float(request.form.get("TRV"))
]
form_data = scaler.transform([form_data])[0]
print(form_data)
prediction = str(deepnet.predict({
"e_prime": form_data[0],
"LVMi": form_data[1],
"A": form_data[2],
"LAVi": form_data[3],
"E_e_prime": form_data[4],
"EF": form_data[5],
"E": form_data[6],
"E_A": form_data[7],
"TRV": form_data[8]
}, full=True))
prediction = ast.literal_eval(prediction)
print(prediction)
## get ip address from the user
ip_address = request.environ['REMOTE_ADDR']
print("ip_address: ", ip_address)
try:
aorticStenosis = AorticStenosis(
ip_address = ip_address,
e_prime = form_data[0],
LVMi = form_data[1],
A = form_data[2],
LAVi = form_data[3],
E_e_prime = form_data[4],
EF = form_data[5],
E = form_data[6],
E_A = form_data[7],
TRV = form_data[8]
)
db.session.add(aorticStenosis)
db.session.commit()
except Exception as e:
print(str(e))
if prediction["prediction"] == "1":
prediction["prediction"] = "Low Risk"
prediction["probability"] = round(
1 - prediction["probability"], 6)
elif prediction["prediction"] == "2":
prediction["prediction"] = "High Risk"
else:
prediction["prediction"] = "No prediction was made!"
return render_template("home.html",
prediction=prediction["prediction"],
probability=prediction["probability"])
else:
return render_template("home.html")
if __name__ == "__main__":
app.run(host="0.0.0.0", port="8000")
I made a new file database.py and defined db there.
database.py
from flask_sqlalchemy import SQLAlchemy
db = SQLAlchemy()
def init_app(app):
db.init_app(app)
app.py
import database
...
database.init_app(app)
models.py
from database import db
...
I am new to REST API and starting building first REST API app using Flask, SQLAlchemy & Marshmallow. This is my app.py file:
from flask import Flask, request, jsonify
from flask_sqlalchemy import SQLAlchemy
from flask_marshmallow import Marshmallow
import os
# Initialize App
app = Flask(__name__)
basedir = os.path.abspath(os.path.dirname(__file__))
# Database Setup
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///' + os.path.join(basedir, 'db.sqlite')
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
# Init db
db = SQLAlchemy(app)
# Init marshmallow
ma = Marshmallow(app)
# Product Class/Model
class Product(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(100), unique=True)
description = db.Column(db.String(200))
price = db.Column(db.Float)
qty = db.Column(db.Integer)
def __init__(self, name, description, price, qty):
self.name = name
self.description = description
self.price = price
self.qty = qty
# Product Schema
class ProductSchema(ma.Schema):
class Meta:
fields = ('id', 'name', 'description', 'price', 'qty')
# Init Schema
product_schema = ProductSchema()
products_schema = ProductSchema(many=True)
# Create Product
#app.route('/product', methods=['POST'])
def add_product():
name = request.json['name']
description = request.json['description']
price = request.json['price']
qty = request.json['qty']
new_product = Product(name, description, price, qty)
db.session.add(new_product)
db.session.commit()
return product_schema.jsonify(new_product)
# Get All Products
#app.route('/receive', methods=['GET'])
def get_products():
all_products = Product.query.all()
result = products_schema.dump(all_products)
return jsonify(result)
# Run the Server
if __name__ == '__main__':
app.run(debug=True)
For generating SQLite database, I have to open python interactive shell and then there I have to do this:
from app import db
db.create_all()
But I have to genreate database from app.py itself so I am inserting the same commands inside app.py, but it's giving me error:
OperationalError: (sqlite3.OperationalError) no such table: product
How do I generate a database from app.py?
Where are you placing your db.create_all()? The error may simply be a result of placement. When I copy and paste your code into PyCharm (running Python 3.7) it creates the DB fine when I place
db.create_all()
immediately before
# Run the Server
if __name__ == '__main__':
app.run(debug=True)
If you try to run db.create_all() before you instantiate the db object it will throw an error because db does not exist yet.
You should not need to use "from app import db" at all because the db object is declared up top.
please; can someone tell me what's wrong with this code?, i tried to connect to my postgre sql database with flask sqlalchemy but i keep having an error that db is not defined. NB: all modules are installed and loaded successfully.
app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql://postgres:....'
db = SQLAlchemy(app)
class Person(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.Text)
age = db.Column(db.Integer)
def __init__(self, name, age):
self.name = name
self.age = age
def __repr__(self):
return "Name:{}\tAge:{}".format(self.name, self.age)
def create_database():
db.create_all()
print('Database created....')
if __name__ == "__main__":
create_database()
First do a pip for sqlalchemy_utils i.e. pip install sqlalchemy_utils
and then,
You need to use engine for creating the DB:
from sqlalchemy import create_engine
from sqlalchemy_utils import database_exists, create_database
engine = create_engine("postgres://localhost/somedb")
if not database_exists(engine.url):
create_database(engine.url)
print(database_exists(engine.url))
I am using Flask with SQLAlchemy and PostGresDB and getting this error on an insert;
sqlalchemy.exc.ProgrammingError: (psycopg2.ProgrammingError) can't adapt type 'dict'
[SQL: 'SELECT results.id AS results_id,......]
models.py is as follows (just the ORM)
class Result(db.Model):
__tablename__ = 'results'
id = db.Column(db.Integer, primary_key=True)
url = db.Column(db.String())
cities = db.Column(JSON)
states = db.Column(JSON)
app.py for the insert part is;
import os
from flask import Flask, render_template, request, jsonify
from flask_sqlalchemy import SQLAlchemy
app = Flask(__name__)
app.config.from_object(os.environ['APP_SETTINGS'])
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = True
db = SQLAlchemy(app)
frequency_cities = Counter(city_pop) # dict object
frequency_states = Counter(state_pop) # dict object
try:
from models import Result
result = Result(
url= url,
cities=frequency_cities,
states=frequency_states
)
db.session.add(result)
db.session.commit()
return result.id
except:
errors.append("Unable to add item to database.")
return {"error": errors}
I am at a loss.
Google and github logins are working properly but for some reason I cant get the facebook and linkedin accounts to properly fill the email fields.
Here are the involved files
__init__.py
db = SQLAlchemy(app)
login_manager=LoginManager()
login_manager.init_app(app)
# Import blueprints from app (example: from app.posts import posts)
from app.users import users
# Register all blueprints to the main app (example: app.register_blueprint(posts))
app.register_blueprint(users)
app.register_blueprint(social_auth)
#3rd part db interaction
init_social(app, db)
# Import main views from app
from app import views
#Set login bootback
login_manager.login_view ='/login'
app.context_processor(backends)
Settings.py configuration, keys have been removed from post
#Flask
SECRET_KEY = ''
SESSION_COOKIE_NAME = ''
### Python Social Auth ###
DEBUG_TB_INTERCEPT_REDIRECTS = False
SESSION_PROTECTION = 'strong'
#Redirects and Paths
SOCIAL_AUTH_LOGIN_URL = '/login'
SOCIAL_AUTH_LOGIN_REDIRECT_URL = '/'
SOCIAL_AUTH_BACKEND_ERROR_URL = '/login'
SOCIAL_AUTH_USER_MODEL = 'app.users.models.User'
SOCIAL_AUTH_USERNAME_IS_FULL_EMAIL = True
#Facebook
SOCIAL_AUTH_FACEBOOK_KEY=''
SOCIAL_AUTH_FACEBOOK_SECRET=''
#Google
SOCIAL_AUTH_GOOGLE_KEY=''
SOCIAL_AUTH_GOOGLE_SECRET=''
#LinkedIn
SOCIAL_AUTH_LINKEDIN_KEY=''
SOCIAL_AUTH_LINKEDIN_SECRET=''
#Github
SOCIAL_AUTH_GITHUB_KEY=''
SOCIAL_AUTH_GITHUB_SECRET=''
SOCIAL_AUTH_AUTHENTICATION_BACKENDS = (
'social.backends.google.GoogleOpenId',
'social.backends.google.GoogleOAuth2',
'social.backends.google.GoogleOAuth',
'social.backends.facebook.FacebookOAuth2',
'social.backends.linkedin.LinkedinOAuth',
'social.backends.github.GithubOAuth2',
)
Here is the model itself, follows pretty closely the example provided by omab
models.py
from __future__ import absolute_import, print_function
from time import time
import functools
import uuid
import pbkdf2
from marshmallow import Serializer, fields
from app import db
ROLE_USER=0
ROLE_ADMIN=1
ROLE_GOD=2
default_img = '/assets/images/avatars/default.jpg'
class User(db.Model):
#meat n' potatoes
id = db.Column(db.Integer, primary_key=True)
img=db.Column(db.String(255), default=default_img)
username = db.Column(db.String(255))
email = db.Column(db.String(200), unique=True)
first_name = db.Column(db.String(30))
last_name = db.Column(db.String(40))
created_at = db.Column(db.BigInteger, default=time())
#controls
role = db.Column(db.SmallInteger, default=ROLE_USER)
is_active = db.Column(db.Boolean, default=True)
is_authenticated= db.Column(db.Boolean, default=True)
#password
salt = db.Column(db.String(50))
pass_hash = db.Column(db.String(255))
def __unicode__(self):
return self.email
def __repr__(self):
return '<User %r>' % self.email
def is_authenticated(self):
return self.is_authenticated
def is_anonymous(self):
return False
def is_active(self):
return self.is_active
def get_id(self):
return unicode(self.id)
def _check_password(self, password):
hash_check = pbkdf2.crypt(password, self.salt, 1000)
if hash_check ==self.pass_hash:
valid=True
else:
valid=False
return valid
def validate_user(self,password):
p=self.check_password(password=password)
if p:
return True;
else:
return False;
meta = {
'allow_inheritance': True,
'indexes': ['-created_at'],
'ordering': ['-created_at']
}
class UserSerializer(Serializer):
id=fields.Integer()
img=fields.String()
email=fields.String()
first_name=fields.String()
last_name=fields.String()
Found this in the docs silly of me not to realize that they would have different request parameters:
http://psa.matiasaguirre.net/docs/backends/index.html
UPDATE:
See this answer from Babken Vardanyan
https://stackoverflow.com/a/46807907/2529583