Here's the `posts.py` file with Pydantic schemas for posts, following the FastAPI project structure with SQLite and SQLAlchemy:


from typing import Optional
from datetime import datetime
from pydantic import BaseModel

class PostBase(BaseModel):
    title: str
    content: str

class PostCreate(PostBase):
    pass

class PostUpdate(PostBase):
    pass

class PostInDBBase(PostBase):
    id: int
    created_at: datetime
    updated_at: Optional[datetime] = None

    class Config:
        orm_mode = True

class Post(PostInDBBase):
    pass

class PostInDB(PostInDBBase):
    pass

Explanation:

1. We import the necessary modules: `typing` for type hints, `datetime` for dealing with date and time objects, and `pydantic` for defining data models.




5. `PostInDBBase` inherits from `PostBase` and includes additional fields: `id`, `created_at`, and `updated_at`. It also sets the `orm_mode` configuration to `True` for compatibility with SQLAlchemy models.