# Author: OMKAR PATHAK

# This is a simple tutorial on usinng SQLAlchemy as ORM (Object Relational Mapping)

# Make sure you have installed SQLAlchemy using: pip3 install sqlalchemy

from sqlalchemy import (

create_engine,

Column,

Integer,

String

)

from sqlalchemy.ext.declarative import declarative_base

from sqlalchemy.orm import sessionmaker

import os

# create a sqlite db

engine = create_engine('sqlite:///example.db', echo=True)

Base = declarative_base()

class Student(Base):

__tablename__ = "student"

id = Column(Integer, primary_key=True)

username = Column(String)

firstname = Column(String)

lastname = Column(String)

university = Column(String)

def __init__(self, username, firstname, lastname, university):

self.username = username

self.firstname = firstname

self.lastname = lastname

self.university = university

def create_tables():

# create tables

Base.metadata.create_all(engine)

if __name__ == '__main__':

sqlite_file = 'example.db'

file_exists = os.path.isfile(sqlite_file)

if not file_exists:

create_tables()

Session = sessionmaker(bind=engine)

session = Session()

# Create objects

user = Student('OmkarPathak', 'Omkar', 'Pathak', 'MIT')

session.add(user)

# commit the record the database

session.commit()

# Select objects

for student in session.query(Student).order_by(Student.id):

print (student.firstname, student.lastname)