Scaffold V2 backend foundation

ai_knowledge_base_v2/apps/backend/app/models/base.py

@@ -0,0 +1,19 @@
+from __future__ import annotations
+
+from datetime import datetime
+
+from sqlalchemy import DateTime, func
+from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+class TimestampMixin:
+    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now(), nullable=False)
+    updated_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now(), onupdate=func.now(), nullable=False)
+
+
+class SoftDeleteMixin:
+    is_deleted: Mapped[int] = mapped_column(default=0, nullable=False)