I am trying to add an user to the database file but i get the following error when trying to create an User object:
sqlalchemy.exc.InvalidRequestError: One or more mappers failed to initialize - can't proceed with initialization of other mappers. Triggering mapper: 'mapped class Patient->patient'. Original exception was: Could not determine join condition between parent/child tables on relationship Patient.documents - there are no foreign keys linking these tables. Ensure that referencing columns are associated with a ForeignKey or ForeignKeyConstraint, or specify a 'primaryjoin' expression.
from flask import Flask, render_template, flash
from flask_sqlalchemy import SQLAlchemy
from forms import LoginForm
app = Flask(__name__)
app.config['SECRET_KEY'] = 'SECRETKEY'
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///storage.db'
db = SQLAlchemy(app)
"""
Users
"""
class User(db.Model):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String)
username = db.Column(db.String, unique=True, nullable=False)
password = db.Column(db.String, nullable=False)
mail = db.Column(db.String, default='test#mail')
role = db.Column(db.Integer)
def __repr__(self):
return f"User('{self.username}', '{self.name}')"
"""
Patients
"""
class Patient(db.Model):
id = db.Column(db.Integer, primary_key=True)
prename = db.Column(db.String, nullable=False)
name = db.Column(db.String, nullable=False)
mail = db.Column(db.String, default='test#mail')
birthdate = db.Column(db.String, nullable=False)
documents = db.relationship('Doc', backref='patient', lazy=True)
def __repr__(self):
return f"Patient('{self.prename}', '{self.name}')"
"""
Documents
"""
class Doc(db.Model):
from datetime import datetime
pdfid = db.Column(db.Integer, primary_key=True)
path = db.Column(db.String)
created = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
deletetime = db.Column(db.Integer, nullable=False)
patientid = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
def __repr__(self):
return f"Docs('{self.path}', '{self.created}')"
My Steps in a python Terminal (the file is called index):
from index import db
db.create_all()
from index import User, Doc, Patient
user1 = User(name='Test User', username='test', password='testtest', role=1)
When I try step 4 I get the above described error.
I don't see any problem in my code so I would appreciate any help :)
Related
I'm struggling to configure my relationships for this database. I can't quite get my head around these relationships and foreign keys and how it all fits together.
I'm trying to have a user who can have multiple posts and multiple projects, but get "primaryjoin" errors ever since I had more than one relationship in the User class.
I would appreaciate any help, I know there have been similar questions asked but I can't seem to map those solutions to my own application.
Here is my models.py file:
from flask_sqlalchemy import SQLAlchemy
from flask_login import UserMixin
from uuid import uuid4
import datetime
from api import app
db = SQLAlchemy(app)
def get_uuid():
return uuid4().hex
today = datetime.date.today()
next_week = today + datetime.timedelta(days=7)
class User(UserMixin, db.Model):
__tablename__ = "users"
id = db.Column(db.String(32), primary_key=True, unique=True, default=get_uuid)
name = db.Column(db.String(60))
email = db.Column(db.String(345), unique=True)
password = db.Column(db.Text, nullable=False)
projects = db.relationship("Project", backref="owner", primaryjoin="users.id == projects.owner_id")
posts = db.relationship("Post", backref="author", primaryjoin="users.id == posts.author_id")
class Project(db.Model):
__tablename__ = "projects"
id = db.Column(db.Integer, primary_key=True)
project_client = db.Column(db.String(60))
word_count = db.Column(db.Integer, nullable=False)
deadline = db.Column(db.DateTime, default=next_week)
completed = db.Column(db.Boolean, default=False)
owner_id = db.Column(db.String, db.ForeignKey("users.id"))
class Post(db.Model):
__tablename__ = "posts"
id = db.Column(db.Integer, primary_key=True)
title = db.Column(db.String(80))
views = db.Column(db.Integer)
author_id = db.Column(db.String, db.ForeignKey("users.id"))
models.py
#login_manager.user_loader
def load_user(username):
return User.query.get(username)
class User(db.Model,UserMixin):
__tablename__ = 'user_accounts'
id = db.Column(db.Integer,primary_key=True)
username = db.Column(db.String(50),unique=True, nullable=False)
email = db.Column(db.String(120), unique=True, nullable=False)
image_file = db.Column(db.String(20),default='default.jpg')
password = db.Column(db.String(80), nullable=False)
task = db.relationship('Tasks', backref='author', lazy=True)
def __repr__(self):
return f'User <{self.id}> {self.username}'
class Tasks(db.Model):
__tablename__ = 'tasks'
id = db.Column(db.Integer,primary_key=True)
title = db.Column(db.String(100),nullable=False)
content = db.Column(db.Text)
user = db.Column(db.String(50),db.ForeignKey('user_accounts.username'),nullable=False)
date_created = db.Column(db.DateTime, default=datetime.datetime.utcnow,nullable=False)
completed = db.Column(db.Boolean,default=False,nullable=False)
def __repr__(self):
return f'{self.title} by {self.user} ({self.date_created})'
Error:
sqlalchemy.exc.NoReferencedTableError: Foreign key associated with column 'tasks.author' could not find table 'user' with which to generate a foreign key to target column 'username'
Here I have a problem that when I trying to run db.create_all() in terminal I am getting the above error message. I am a bit confused in the usage of backref for db.relationship as my target is to represent a user could have specific task and a task is owned by that user so may I ask how could I properly organize the relationship between two tables in order to create a table with no error messages?
I am creating a server application that will utilize a remote database created by a Flask GUI. To keep things simple (and since it's primarily threaded calculations), I want to build my server application without utilizing a Flask framework. I will have a redis message server to keep the two processes in sync.
My challenge is that I want to use persistent storage wherever possible. So as part of this, my server application will need to import the Flask-SQLAlchemy database files to retrieve the parameters. The difficulty I am having is to write the import statement that will pull the SQLAlchemy files into pandas. Here is what I have so far:
config.py
import os
class Config:
SQLALCHEMY_DATABASE_URI_REMOTE = os.environ.get('RDQ_LOGIN') # remote docker database
SQLALCHEMY_DATABASE_URI_LOCAL = os.environ.get('RDU_LOGIN') # local file database
REDIS_IP = os.environ.get('REDIS_IP')
REDIS_PASSWORD = os.environ.get('REDIS_PASSWORD')
init.py
from src_code.config import Config
import redis
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
from sqlalchemy import orm
from sqlalchemy.ext.declarative import declarative_base
import sqlalchemy as sa
engine_remote = create_engine(Config.SQLALCHEMY_DATABASE_URI_REMOTE, echo=True)
Base_remote = declarative_base()
Base_remote.metadata.create_all(engine_remote)
Session_remote = sessionmaker(bind=engine_remote)
Session_remote.configure(bind=engine_remote)
session_remote = Session_remote()
engine_local = create_engine(Config.SQLALCHEMY_DATABASE_URI_LOCAL, echo=True)
Base_local = declarative_base()
Base_local.metadata.create_all(engine_local)
Session_local = sessionmaker(bind=engine_local)
Session_local.configure(bind=engine_local)
session_local = Session_local()
redisChannel = redis.StrictRedis(host=Config.REDIS_IP, port=6379, password=Config.REDIS_PASSWORD,
decode_responses=True)
main.py
import pandas as pd
from src_code import session_local, session_remote
def start():
table_df = pd.read_sql(
'SELECT * from game',
con=session_remote
)
print(table_df)
if __name__ == "__main__":
start()
Unfortunately I am getting an error:
AttributeError: 'Session' object has no attribute 'cursor'
I don't need to be able to write back to the table (so read-only is sufficient). So I am using a simple example that would give me the ability to extract what I need from the panda (I am more confident to use pandas than SQL).
I do have the model statements that I could replicate in the server code if this would somehow facilitate the process:
from datetime import datetime
from itsdangerous import TimedJSONWebSignatureSerializer as Serializer
from flask import current_app
from src_code import db, login_manager
from flask_login import UserMixin
#login_manager.user_loader
def load_user(user_id):
return User.query.get(int(user_id))
class User(db.Model, UserMixin):
id = db.Column(db.Integer, primary_key=True)
username = db.Column(db.String(20), unique=True, nullable=False)
email = db.Column(db.String(120), unique=True, nullable=False)
agent = db.Column(db.Integer, unique=False, nullable=False)
image_file = db.Column(db.String(20), unique=False, nullable=False,default='default.jpg')
password = db.Column(db.String(60), nullable=False)
posts = db.relationship('Post', backref='author', lazy=True)
games_started = db.relationship('Game', backref='captained', lazy=True)
games_played = db.relationship('Player', backref='games', lazy=True)
def get_reset_token(self, expires_sec=1800):
s = Serializer(current_app.config['SECRET_KEY'], expires_sec)
return s.dumps({'user_id': self.id}).decode('utf-8')
#staticmethod
def verify_reset_token(token):
s = Serializer(current_app.config['SECRET_KEY'])
try:
user_id = s.loads(token)['user_id']
except:
return None
return User.query.get(user_id)
def __repr__(self):
return f"User('{self.username}', '{self.email}', '{self.agent}', '{self.image_file}')"
class Post(db.Model):
id = db.Column(db.Integer, primary_key=True)
title = db.Column(db.String(100), nullable=False)
date_posted = db.Column(db.DateTime, nullable=False,default=datetime.utcnow)
content = db.Column(db.Text, nullable=False)
user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
def __repr__(self):
return f"Post('{self.title}', '{self.date_posted}')"
class Game(db.Model):
id = db.Column(db.Integer, primary_key=True)
title = db.Column(db.String(60), nullable=False)
date_posted = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
company_count = db.Column(db.Integer, nullable=False)
starting_year = db.Column(db.Integer, nullable=False)
time_limit = db.Column(db.Integer, nullable=False)
agent_decisions_visible = db.Column(db.Boolean, nullable=False)
client_count = db.Column(db.Integer, nullable=False)
pre_game_yrs = db.Column(db.Integer, nullable=False)
time_index = db.Column(db.Integer, nullable=False)
game_active = db.Column(db.Boolean, nullable=False)
player_capt = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
games_msgs = db.relationship('Messages', backref='messages', lazy=True)
def __repr__(self):
return f"Game('{self.title}', '{self.date_posted}')"
class GameRequests(db.Model):
id = db.Column(db.Integer, primary_key=True)
date_requested = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
game_id = db.Column(db.Integer, db.ForeignKey('game.id'), nullable=False)
user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
def __repr__(self):
return f"GameRequest('{self.game_id}', '{self.user_id}', '{self.date_requested}'"
class GameDecisions(db.Model):
id = db.Column(db.Integer, primary_key=True)
date_requested = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
game_id = db.Column(db.Integer, db.ForeignKey('game.id'), nullable=False)
user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
time_index = db.Column(db.Integer, nullable=False)
def __repr__(self):
return f"GameDecisions('{self.game_id}', '{self.user_id}', '{self.time_index}'"
class Player(db.Model):
id = db.Column(db.Integer, primary_key=True)
date_posted = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
game_id = db.Column(db.Integer, db.ForeignKey('game.id'), nullable=False)
user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
def __repr__(self):
return f"Player('{self.game_id}', '{self.user_id}', '{self.date_posted}'"
class Messages(db.Model):
id = db.Column(db.Integer, primary_key=True)
date_posted = db.Column(db.DateTime, nullable=False,default=datetime.utcnow)
type = db.Column(db.String(10), nullable=False)
msg_from = db.Column(db.String(20), nullable=False)
msg_to = db.Column(db.String(20), nullable=False)
message = db.Column(db.String(60), nullable=False)
game_id = db.Column(db.Integer, db.ForeignKey('game.id'), nullable=False)
def __repr__(self):
return f"Messages('{self.game_id}', '{self.id}', '{self.message}', '{self.date_posted}')"
Thanks for any help you can offer!
Similar to your conclusion, here's how I read databases into pandas:
# Create your query.
# This can be as complex or simple as you'd like
query = session_remote.query(Game)
df = pd.read_sql(query.statement, session_remote.bind)
The key difference here is the utilization of the ORM to perform (or rather, write) the query itself.
Masking SQL behind an ORM has many advantages -- I strongly recommend against utilizing raw SQL in production backends.
It seems I was closer than I realized. The following code did what I needed:
SQLAlchemy ORM conversion to pandas DataFrame
table_df = pd.read_sql(
'SELECT * from game',
session_remote.bind
)
So I am working on a forum-like website for discussions using the python framework Flask. I set up a database using SQLite. I defined two tables (classes) and made primary keys for both. However, the primary keys they produce are the same. For example, for the first set of data, the primary key is 1 for both and I can't differentiate between the two sets of data. I can access the first table's data if I need to, but when I try to get the second table's data, it gives me the first tables data again. Is there any way to have two unique primary keys for both or do I have to set up two different databases.
from datetime import datetime
from flaskblog import db, login_manager
from flask_login import UserMixin
#login_manager.user_loader
def load_user(user_id):
return User.query.get(int(user_id))
class User(db.Model, UserMixin):
id = db.Column(db.Integer, primary_key=True)
username = db.Column(db.String(20), unique=True, nullable=False)
email = db.Column(db.String(120), unique=True, nullable=False)
image_file = db.Column(db.String(20), nullable=False, default='default.jpg')
password = db.Column(db.String(60), nullable=False)
posts = db.relationship('Post', backref='author', lazy=True)
posts_addmath = db.relationship('PostAddmath', backref='author', lazy=True)
def __repr__(self):
return f"User('{self.username}', '{self.email}', '{self.image_file}')"
class Post(db.Model):
id = db.Column(db.Integer, primary_key=True)
title = db.Column(db.String(100), nullable=False)
date_posted = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
content = db.Column(db.Text, nullable=False)
user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
def __repr__(self):
return f"Post('{self.title}', '{self.date_posted}')"
class PostAddmath(db.Model):
id = db.Column(db.Integer, primary_key=True)
title = db.Column(db.String(100), nullable=False)
date_posted = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
content = db.Column(db.Text, nullable=False)
user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
def __repr__(self):
return f"Post('{self.title}', '{self.date_posted}')"
These are the tables in models.py.
id_addmath = db.Column(db.Integer, primary_key=True)
I tried changing the 'id' variable in the 'PostAddmath' class but that didn't work.
#app.route("/post/<int:post_id>")
#login_required
def post_intmath(post_id):
post = Post.query.get_or_404(post_id)
return render_template('subjects/intmath/post_intmath.html', title=post.title, post=post)
#app.route("/post/<int:post_id>")
#login_required
def post_addmath(post_id):
post = PostAddmath.query.get_or_404(post_id)
return render_template('subjects/addmath/post_addmath.html', title=post.title, post=post)
This is how a access the data in my routes.py.
When I try to access the data using 'post.id' it gives me only the first tables results not the send tables.
If I have to set up a different database please let me know how to do so. Any help is greatly appreciated. Thank You.
You have the same route to both post_intmath and to post_addmath you have to change the routes for example the first route keep it as it is /post/<int:post_id> and the second route change it to /addpost/<int:post_id> for example.
I'm trying to add RBAC to my existing flask application where I already have 2 models which describe User and Post model respectively. Here is my code:
# models.py
from datetime import datetime
from rpd_site import db, login_manager
from flask_login import UserMixin
# []
#login_manager.user_loader
def load_user(user_id):
return User.query.get(int(user_id))
# Main site account table
class User(db.Model, UserMixin):
id = db.Column(db.Integer, primary_key=True)
username = db.Column(db.String(20), unique=True, nullable=False)
email = db.Column(db.String(120), unique=True, nullable=False)
image_file = db.Column(db.String(20), nullable=False, default='default.jpg')
password = db.Column(db.String(60), nullable=False)
confirmed = db.Column(db.Boolean, nullable=False, default=0)
posts = db.relationship('Post', backref='author', lazy=True)
def __repr__(self):
return f"User('{self.username}', '{self.email}', '{self.confirmed}')"
# Posts table
class Post(db.Model):
id = db.Column(db.Integer, primary_key=True)
title = db.Column(db.String(100), nullable=False)
date_posted = db.Column(db.DateTime, nullable=False, default=datetime.now) # current local time instead of .utcnow
content = db.Column(db.Text, nullable=False)
user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
image_file = db.Column(db.String(20), nullable=False, default='default_post.png')
def __repr__(self):
return f"Post('{self.title}', '{self.date_posted}', '{self.content[:15]}')"
When I tried add all missing code from here I faced with lots of errors. Especially I'm not sure if I should import UserMixin from flask_rbac or from flask_login.
Help me to understand how can I upgrade my DB with RBAC functionality.
This is a very broad question, I'll try to give you a minimum code so that you can achieve RBAC. Below example uses Flask-security.
from app import db
from flask_security import RoleMixin, UserMixin
# may to many association table between User and Role
roles_users = db.Table(
'roles_users',
db.Column('user_id', db.Integer(), db.ForeignKey('user.id')),
db.Column('role_id', db.Integer(), db.ForeignKey('role.id'))
)
class Role(db.Model, RoleMixin):
__tablename__ = 'role'
id = db.Column(db.Integer(), primary_key=True)
name = db.Column(db.String(50), unique=True)
def __str__(self):
return self.name
class User(db.Model, UserMixin):
__tablename__ = 'user'
id = db.Column(db.Integer, primary_key=True)
email = db.Column(db.String(50), unique=True)
password = db.Column(db.String(255))
roles = db.relationship('Role', secondary=roles_users,
backref=db.backref('users', lazy='joined'))
def __str__(self):
return self.email
You either migrate or create the DB based on above Models. The above will be sufficient for you to either perform back-end operation for RDBC or at view level.
You can then assign roles to each user easily using below link.
Flask-security create role,user and linking user_id to role_id
If you want to perform RBAC at view, follow below.
from flask_security import login_required, roles_accepted
#app.route('/a_restricted_view/')
#login_required
#roles_accepted('role_one', 'role_two')
def a_restricted_view():
return "I am only visible to users with role_one and role_two"