CRUD DynamoDB from Python (PynamoDB)

In this post, I am goint to use DynamoDB from PynamoDB.

You may compare the code with CRUD DynamoDB from Python (boto3)

what is PynamoDB?

PynamoDB is "a Pythonic interface for Amazon's DynamoDB"

https://github.com/pynamodb/PynamoDB

install

% pip install pynamodb
% pip list | grep pynamo
pynamodb                           5.0.3

student.py

You can define the entity like:

from pynamodb.attributes import UnicodeAttribute
from pynamodb.models import Model

class Student(Model):
  class Meta:
    table_name = 'student'
    host = 'http://localhost:8000' # region = 'us-east-1'
    write_capacity_units = 5 
    read_capacity_units = 5 

  id = UnicodeAttribute(hash_key=True)
  grade = UnicodeAttribute(null=True)

You may remove the host = localhost (and optionally specify the region) to run it on the cloud.

test.py

from student import Student

# create table (wait for creation)
if not Student.exists():
  Student.create_table(wait=True)

# insert
s1 = Student('001')
s1.save()
print(s1.id) # 001

Student('002', grade='B').save()

# select
s2 = Student.get('002')
print(s2.id + ',' + s2.grade) # 002,B

# update
s1.update(actions=[
  Student.grade.set('A')
])
print(s1.id + ',' + s1.grade) # 001,A

# delete
s1.delete()

# drop table
Student.delete_table()