Here's the `posts.py` file for the `blog_app_svkgt` FastAPI backend, defining a SQLAlchemy model for posts:


from sqlalchemy import Column, Integer, String, Text, ForeignKey
from sqlalchemy.orm import relationship
from sqlalchemy.sql.sqltypes import TIMESTAMP
from sqlalchemy.sql import func

from app.db import Base

class Post(Base):
    __tablename__ = "posts"

    id = Column(Integer, primary_key=True, index=True)
    title = Column(String, nullable=False)
    content = Column(Text, nullable=False)
    created_at = Column(TIMESTAMP, server_default=func.now())
    updated_at = Column(TIMESTAMP, server_default=func.now(), onupdate=func.now())
    user_id = Column(Integer, ForeignKey("users.id"))

    user = relationship("User", back_populates="posts")

    def __repr__(self):
        return f"Post(id={self.id}, title='{self.title}', content='{self.content[:20]}...')"

Explanation:

5. The `title` column is a `String` column marked as `nullable=False`, meaning it cannot be null.
6. The `content` column is a `Text` column marked as `nullable=False`, allowing for longer text content.
7. The `created_at` column is a `TIMESTAMP` column with a default value set to the current server time using `func.now()`.
8. The `updated_at` column is a `TIMESTAMP` column with a default value set to the current server time using `func.now()`, and it will be updated with the current time whenever the row is updated using `onupdate=func.now()`.