refactor: 去除 UserMixin 审计字段外键约束以消除循环外键

sys_user.dept_id 与 sys_dept（UserMixin 审计字段）互为外键形成循环依赖。原 dept_id 用 use_alter=True 规避，但 use_alter 在 Alembic autogenerate 下会被内联进 op.create_table，PostgreSQL 编译时跳过导致外键静默丢失。

移除 created_id/updated_id/deleted_id 三个审计字段指向 sys_user 的外键约束（ondelete=SET NULL 已允许悬空，审计字段无需强引用），并为 created_by/updated_by/deleted_by 关系显式补充 primaryjoin。循环依赖消除后，dept_id 的 use_alter 亦可移除，autogenerate 可正确生成迁移。

Author: SmallGaoX

backend/app/core/base_model.py

@@ -1,6 +1,6 @@
 from datetime import UTC, datetime
 
-from sqlalchemy import Boolean, DateTime, ForeignKey, Index, Integer, MetaData, String
+from sqlalchemy import Boolean, DateTime, Index, Integer, MetaData, String
 from sqlalchemy.ext.asyncio import AsyncAttrs
 from sqlalchemy.orm import DeclarativeBase, Mapped, declared_attr, mapped_column, relationship
 
@@ -132,15 +132,13 @@ class UserMixin(MappedBase):
 
     created_id: Mapped[int | None] = mapped_column(
         Integer,
-        ForeignKey("sys_user.id", ondelete="SET NULL", onupdate="CASCADE"),
         default=None,
         nullable=True,
         index=True,
         comment="创建人ID",
     )
     updated_id: Mapped[int | None] = mapped_column(
         Integer,
-        ForeignKey("sys_user.id", ondelete="SET NULL", onupdate="CASCADE"),
         default=None,
         nullable=True,
         index=True,
@@ -149,7 +147,6 @@ class UserMixin(MappedBase):
 
     deleted_id: Mapped[int | None] = mapped_column(
         Integer,
-        ForeignKey("sys_user.id", ondelete="SET NULL", onupdate="CASCADE"),
         default=None,
         nullable=True,
         index=True,
@@ -161,7 +158,7 @@ def created_by(self):
         """创建人关联关系"""
         return relationship(
             "UserModel",
-            foreign_keys=lambda: self.created_id,  # pyright: ignore[reportArgumentType]
+            primaryjoin=f"foreign({self.__name__}.created_id) == remote(UserModel.id)",
             uselist=False,
         )
 
@@ -170,7 +167,7 @@ def updated_by(self):
         """更新人关联关系"""
         return relationship(
             "UserModel",
-            foreign_keys=lambda: self.updated_id,  # pyright: ignore[reportArgumentType]
+            primaryjoin=f"foreign({self.__name__}.updated_id) == remote(UserModel.id)",
             uselist=False,
         )
 
@@ -179,6 +176,6 @@ def deleted_by(self):
         """删除人关联关系"""
         return relationship(
             "UserModel",
-            foreign_keys=lambda: self.deleted_id,  # pyright: ignore[reportArgumentType]
+            primaryjoin=f"foreign({self.__name__}.deleted_id) == remote(UserModel.id)",
             uselist=False,
         )

backend/app/modules/system/user/model.py

@@ -81,10 +81,25 @@ class UserModel(ModelMixin, UserMixin):
     status: Mapped[int] = mapped_column(Integer, default=0, nullable=False, comment="状态(0:启动 1:停用)")
     description: Mapped[str | None] = mapped_column(Text, default=None, nullable=True, comment="备注")
 
-    dept_id: Mapped[int | None] = mapped_column(Integer, ForeignKey("sys_dept.id", ondelete="SET NULL", onupdate="CASCADE", use_alter=True), nullable=True, index=True, comment="部门ID")
+    dept_id: Mapped[int | None] = mapped_column(Integer, ForeignKey("sys_dept.id", ondelete="SET NULL", onupdate="CASCADE"), nullable=True, index=True, comment="部门ID")
     dept: Mapped["DeptModel | None"] = relationship(back_populates="users", foreign_keys=[dept_id])
     roles: Mapped[list["RoleModel"]] = relationship(secondary="sys_user_roles", back_populates="users")
     positions: Mapped[list["PositionModel"]] = relationship(secondary="sys_user_positions", back_populates="users")
-    created_by: Mapped["UserModel | None"] = relationship("UserModel", foreign_keys="UserModel.created_id", remote_side="UserModel.id", uselist=False, viewonly=True)
-    updated_by: Mapped["UserModel | None"] = relationship("UserModel", foreign_keys="UserModel.updated_id", remote_side="UserModel.id", uselist=False, viewonly=True)
-    deleted_by: Mapped["UserModel | None"] = relationship("UserModel", foreign_keys="UserModel.deleted_id", remote_side="UserModel.id", uselist=False, viewonly=True)
+    created_by: Mapped["UserModel | None"] = relationship(
+        "UserModel",
+        primaryjoin="foreign(UserModel.created_id) == remote(UserModel.id)",
+        uselist=False,
+        viewonly=True,
+    )
+    updated_by: Mapped["UserModel | None"] = relationship(
+        "UserModel",
+        primaryjoin="foreign(UserModel.updated_id) == remote(UserModel.id)",
+        uselist=False,
+        viewonly=True,
+    )
+    deleted_by: Mapped["UserModel | None"] = relationship(
+        "UserModel",
+        primaryjoin="foreign(UserModel.deleted_id) == remote(UserModel.id)",
+        uselist=False,
+        viewonly=True,
+    )