Model stocks.py
Blog & code on model and API stocks.py
Model stocks.py
from random import randrange
from datetime import date
import os, base64
import json
from __init__ import app, db
from sqlalchemy.exc import IntegrityError
from werkzeug.security import generate_password_hash, check_password_hash
class Stock(db.Model):
__tablename__ = 'stocks' # table name is plural, class name is singular
# Define the User schema with "vars" from object
id = db.Column(db.Integer, primary_key=True)
_name = db.Column(db.String(255), unique=False, nullable=False)
_ticker = db.Column(db.String(255), unique=False, nullable=False)
_rating = db.Column(db.String(255), unique=False, nullable=False)
# constructor of a User object, initializes the instance variables within object (self)
def __init__(self, name, ticker, rating="neutral"):
self._name = name # variables with self prefix become part of the object,
self._ticker = ticker
self._rating = rating
# a name getter method, extracts name from object
@property
def name(self):
return self._name
# a setter function, allows name to be updated after initial object creation
@name.setter
def name(self, name):
self._name = name
# a getter method, extracts email from object
@property
def ticker(self):
return self._ticker
# a setter function, allows name to be updated after initial object creation
@ticker.setter
def ticker(self, ticker):
self._ticker = ticker
@property
def rating(self):
return self._rating
# a setter function, allows name to be updated after initial object creation
@rating.setter
def rating(self, rating):
self._rating = rating
# output content using str(object) in human readable form, uses getter
# output content using json dumps, this is ready for API response
def __str__(self):
return json.dumps(self.read())
# CRUD create/add a new record to the table
# returns self or None on error
def create(self):
try:
# creates a person object from User(db.Model) class, passes initializers
db.session.add(self) # add prepares to persist person object to Users table
db.session.commit() # SqlAlchemy "unit of work pattern" requires a manual commit
return self
except IntegrityError:
db.session.remove()
return None
# CRUD read converts self to dictionary
# returns dictionary
def read(self):
return {
"id": self.id,
"name": self.name,
"ticker": self.ticker,
"rating": self.rating,
}
# CRUD update: updates user name, password, phone
# returns self
def update(self, name="", ticker="", rating=""):
"""only updates values with length"""
if len(name) > 0:
self.name = name
if len(ticker) > 0:
self.ticker = ticker
if len(rating) > 0:
self.rating = rating
db.session.commit()
return self
# CRUD delete: remove self
# None
def delete(self):
db.session.delete(self)
db.session.commit()
return None
## Created a database that stores stocks above
"""Database Creation and Testing """
# Builds working data for testing
def initStocks():
"""Create database and tables"""
db.create_all()
"""Tester data for table"""
s1 = Stock(name='APPLE<', ticker='APPL', rating='STONG SELL')
s2 = Stock(name='NVIDIA', ticker='NVDA', rating='STRONG BUY')
s3 = Stock(name='EXXON MOBILE', ticker='XOM', rating='NEUTRAL')
stocks = [s1, s2, s3,]
"""Builds sample user/note(s) data"""
for stock in stocks:
try:
'''add user/post data to table'''
stock.create()
except IntegrityError:
'''fails with bad or duplicate data'''
db.session.remove()
print(f"Records exist, duplicate email, or error: {stock.id}")