Added SQLAlchemy and Alembic to work with Postgres

db/data.py

@@ -0,0 +1,53 @@
+import os
+from os.path import dirname, join
+from typing import List, Optional
+from uuid import UUID
+
+from dotenv import load_dotenv
+from sqlalchemy import ForeignKey, create_engine
+from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column, relationship
+
+load_dotenv(join(dirname(__file__), '..', '.env'))
+DATABASE_PASSWORD=os.getenv('DATABASE_PASSWORD')
+DATABASE_NAME=os.getenv('DATABASE_NAME')
+DATABASE_USER=os.getenv('DATABASE_USER')
+DATABASE_PORT=os.getenv('DATABASE_PORT')
+DATABASE_HOST=os.getenv('DATABASE_HOST')
+engine = create_engine(f"postgresql+psycopg2://{DATABASE_USER}:{DATABASE_PASSWORD}@{DATABASE_HOST}:{DATABASE_PORT}/{DATABASE_NAME}", echo=True)
+
+
+class Base(DeclarativeBase):
+    pass
+
+class User(Base):
+    __tablename__ = 'user'
+    
+    id: Mapped[int] = mapped_column(primary_key=True)
+    user_name: Mapped[Optional[str]]
+    
+    admin: Mapped['Admin'] = relationship(back_populates='user', cascade='all, delete-orphan')
+    
+    def __repr__(self) -> str:
+        return f'User(id={self.id!r}, user_name={self.user_name!r})'
+
+    def __str__(self) -> str:
+        return f'User(id={self.id!r}, user_name={self.user_name!r})'
+    
+class Admin(Base):
+    __tablename__ = 'admin'
+    
+    user_id: Mapped[int] = mapped_column(ForeignKey('user.id'), primary_key=True)
+    user: Mapped['User'] = relationship(back_populates='admin')
+    posts: Mapped[List['Post']] = relationship(back_populates='user', cascade='all, delete')
+
+class Post(Base):
+    __tablename__ = 'post'
+    
+    uuid: Mapped[UUID] = mapped_column(primary_key=True)
+    from_user_id: Mapped[int] = mapped_column(ForeignKey('admin.user_id'))
+    user: Mapped['Admin'] = relationship(back_populates='posts')
+    text: Mapped[str]
+    images: Mapped[str]
+    
+if __name__ == '__main__':
+    Base.metadata.create_all(engine)