SQLAlchemy ForeignKey Constraints

     # SQLAlchemy-1.3.20

# pip install pymysql

from sqlalchemy import (create_engine, Float, Text, MetaData, 

Table, Column, Integer, String, DateTime,

ForeignKey)

from datetime import datetime

meta_data = MetaData()

db_connection = 'mysql+pymysql://root:india@123@localhost/sql_alchemy'

# db_connection = 'mysql+pymysql://username:pasword@localhost/db_name'

#table = Model

users = Table('users', meta_data,

Column('user_id', Integer(), primary_key = True),

Column('username', String(15), nullable = False, unique = True),

Column('email', String(150), nullable = False),

Column('password', String(12), nullable = False),

Column('created_on', DateTime(),default=datetime.now,nullable = False),

Column('update_on', DateTime(), default=datetime.now, onupdate=datetime.now,nullable = False)

)

dish_items = Table('dish_items', meta_data,

Column('dish_id', Integer(), primary_key= True),

Column('rate', Float(),nullable = False, default = 1.0),

Column('name', String(100), nullable=False),

Column('recipe', Text(), nullable =True )

)

order = Table('order', meta_data,

Column('order_id', Integer(), primary_key = True),

Column('user_id', ForeignKey('users.user_id'),nullable = False),

Column('created_on', DateTime(),default=datetime.now,nullable = False),

)

bill = Table('bill', meta_data,

Column('bill_id', Integer(), primary_key = True),

Column('order_id', ForeignKey('order.order_id'), nullable = False),

Column('dish_id', ForeignKey('dish_items.dish_id'), nullable = False),

Column('bill_rate', Float(), nullable = False),

Column('quantity', Integer(), nullable = False)

)

engine = create_engine(db_connection)

try:

  conn = engine.connect()

  print('db connected')

  print('connection object is :{}'.format(conn))

except: 

  print('db not connected')

meta_data.create_all(engine)

user_tom = users.insert().values(

username="tom",

email="tom@gmail.com",

password="12345",

)

user_jarry = users.insert().values(

username="jarry",

email="jarry@gmail.com",

password="12345",

)

dish_1 = dish_items.insert().values(

rate= 3.4,

name= 'Farm Fresh Pizza',

recipe= 'Onion, tomato, capsicum and mushroom.'

)

dish_2 = dish_items.insert().values(

rate= 2.4,

name= 'Cheese and Corn Pizza',

recipe= 'Corn and cheese.'

)

dish_3 = dish_items.insert().values(

rate= 4.4,

name= 'Spicy Paneer Pizza',

recipe= 'Sweet corn,jalapeno and red paprika.'

)

dish_4 = dish_items.insert().values(

rate= 3.4,

name= 'Veg Double Pizza Combo',

recipe= 'Onion and paneer,onion and capsicum,tomato and sweet corn,jalapeno and onion.'

)

# print(ins.compile().params)

result = conn.execute(user_tom )

result = conn.execute(user_jarry)

result = conn.execute(dish_1)

result = conn.execute(dish_2)

result = conn.execute(dish_3)

result = conn.execute(dish_4)

# print('Last inserted key:')

# print(result.inserted_primary_key)