from sqlalchemy import Column, Integer, String, Text, ForeignKey, DateTime from datetime import datetime from app.database import Base class Message(Base): __tablename__ = "messages" id = Column(Integer, primary_key=True, index=True) conversation_id = Column( Integer, ForeignKey("conversations.id") ) role = Column(String) content = Column(Text) created_at = Column( DateTime, default=datetime.utcnow )