import sqlalchemy
from sqlalchemy import Column, create_engine, ForeignKey
from sqlalchemy.types import Integer, VARCHAR, TEXT, DateTime
from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()

class Author(Base):
  __tablename__ = 'authors'

  id = Column(Integer, primary_key=True)
  name = Column(VARCHAR(30), unique=True, nullable=False)
  updated_on = Column(DateTime, nullable=False)

  def __repr__(self):
    return f'{self.id}\t{self.name}\t{self.updated_on}\n'


class Post(Base):
  __tablename__ = 'posts'

  id = Column(Integer, primary_key=True)
  title = Column(VARCHAR(50), unique=True, nullable=False)
  content = Column(TEXT, unique=True, nullable=False)
  author_id = Column(Integer, ForeignKey('authors.id'), nullable=False)
  published_on = Column(DateTime, nullable=False)

  def __repr__(self):
    return f"""{self.id}\t{self.title}
    {self.content}\n{self.author_id}\t{self.published_on}"""

engine = create_engine('sqlite:///blog.db', echo=True)
Base.metadata.create_all(bind=engine)