• Create an engine

• Create session

• Create a table

• Migrate

Getting Started

Open your code editor (vs code) save the file students.py navigate to the directory of students.py from the terminal on your vs code

HOW TO CREATE AN ENGINE

from the terminal, run these

-  pip3 install sqlalchemy

- pip3 install psycopg2

from sqlalchemy import create_engine

engine = create_engine('postgresql://rukayat:rukayat@localhost:5432.., echo=False) ###to create an engine using postgresql

HOW TO CREATE A SESSION

from sqlalchemy.orm import session, sessionmaker

Session = sessionmaker(bind=engine) session = Session()

HOW TO CREATE A TABLE

from sqlalchemy import create_engine, Column, String, Integer Base = declarative_base()

class Student(Base):
    __tablename__ = 'student'
    id = Column(Integer, primary_key=True)
    name = Column(String(50))
    age = Column(Integer)
    grade = Column(String(50))

#Migrate

Base.metadata.create_all(engine) ##This will create a table in the database

go to your terminal, run python3 students.py ###I saved my file as students.py

#To check if it has been created

• Go to your pg4admin -nagivate t0 Schema
• locate table

![Screenshot 2022-05-01 at 11.33.10.png] (cdn.hashnode.com/res/hashnode/image/upload/.. align="left")

HOW TO INSERT DATA INTO THE TABLE

1. Create instance of table class

2. Add data to session

3. Commit changes to database

student1 = Student(name='Will', age='24', grade='A')

session.add(student1)

session.commit()

### To add multiple inputs at the same time

student2 = Student(name='Shile', age='27', grade='B')

student3 = Student(name='Harry', age='25', grade='C')

session.add_all([student2, student3])

HOW TO READ DATA FROM THE TABLE

###Get data by Order
students = session.query(Student).order_by(Student.name)

for student in students:
   print(student.name)

###Get data by filter
students = session.query(Student).filter(Student.name=='Will').first()

print(students.name, students.grade)

students = session.query(Student).filter(or_(Student.name=='Will', Student.name=='Shile'))

for student in students:
    print(student.name)

#Count the number of results
student_count = session.query(Student).filter(or_(Student.name=='Will', Student.name=='Shile')).count()
print(student_count)

for more information, check out the docs click here

UPDATE DATA FROM THE TABLE

1. Get the record
2. Update the record
3. Commit the change

student = session.query(Student).filter(Student.name=='Shile').first()

student.name = 'Kelvin'

session.commit()

DELETE DATA FROM THE TABLE

1. Get the record
2. Delete the record
3. Commit the change

student = session.query(Student).filter(Student.name=='Kelvin').first()
session.delete(student)
session.commit()

After deletion, this is what my table looks like