feat: 支持先绑定设备后关联儿童档案

- 绑定模型新增 owner_user_id，支持 child_id 为空\n- 新增绑定后设置儿童接口 /bindings/{device_id}/child\n- 前端绑定页改为先绑设备后补充儿童\n- 补充数据库迁移脚本与 DAO 测试用例

mini-program/app/dao/binding.py

@@ -5,6 +5,7 @@ from datetime import datetime, timedelta
 from typing import Optional
 
 from sqlalchemy import text
+from sqlalchemy.exc import IntegrityError
 
 from app.dao import BaseDAO
 
@@ -12,7 +13,172 @@ logger = logging.getLogger("app.dao.binding")
 
 
 class BindingDAO(BaseDAO):
-    def start_bind(self, user_id: int, device_id: str, child_id: int) -> str:
+    def _upsert_parent_child_relation(self, user_id: int, child_id: int) -> None:
+        updated = self.db.execute(
+            text(
+                """
+                UPDATE parent_child_relations
+                SET status = 1,
+                    updated_at = CURRENT_TIMESTAMP
+                WHERE user_id = :user_id
+                  AND child_id = :child_id
+                """
+            ),
+            {"user_id": user_id, "child_id": child_id},
+        )
+        if updated.rowcount and updated.rowcount > 0:
+            return
+
+        try:
+            self.db.execute(
+                text(
+                    """
+                    INSERT INTO parent_child_relations (user_id, child_id, relation_type, is_primary, status)
+                    VALUES (:user_id, :child_id, 9, 0, 1)
+                    """
+                ),
+                {"user_id": user_id, "child_id": child_id},
+            )
+        except IntegrityError:
+            # Handle race: another transaction inserted the same (user_id, child_id) row.
+            self.db.execute(
+                text(
+                    """
+                    UPDATE parent_child_relations
+                    SET status = 1,
+                        updated_at = CURRENT_TIMESTAMP
+                    WHERE user_id = :user_id
+                      AND child_id = :child_id
+                    """
+                ),
+                {"user_id": user_id, "child_id": child_id},
+            )
+
+    def _insert_bind_history(self, device_id: str, child_id: Optional[int], user_id: int, bind_source: int) -> None:
+        self.db.execute(
+            text(
+                """
+                INSERT INTO device_bind_history (device_id, child_id, bound_by_user_id, bind_source, bound_at)
+                VALUES (:device_id, :child_id, :user_id, :bind_source, CURRENT_TIMESTAMP)
+                """
+            ),
+            {
+                "device_id": device_id,
+                "child_id": child_id,
+                "user_id": user_id,
+                "bind_source": bind_source,
+            },
+        )
+
+    def _bind_device(self, device_id: str, user_id: int, child_id: Optional[int]) -> None:
+        existing_by_device = (
+            self.db.execute(
+                text("SELECT id FROM device_bindings WHERE device_id = :device_id"),
+                {"device_id": device_id},
+            )
+            .mappings()
+            .first()
+        )
+
+        if child_id is None:
+            if existing_by_device:
+                self.db.execute(
+                    text(
+                        """
+                        UPDATE device_bindings
+                        SET owner_user_id = :owner_user_id,
+                            child_id = NULL,
+                            status = 1,
+                            unbound_at = NULL,
+                            updated_at = CURRENT_TIMESTAMP
+                        WHERE device_id = :device_id
+                        """
+                    ),
+                    {"owner_user_id": user_id, "device_id": device_id},
+                )
+            else:
+                self.db.execute(
+                    text(
+                        """
+                        INSERT INTO device_bindings (device_id, owner_user_id, child_id, status, bound_at)
+                        VALUES (:device_id, :owner_user_id, NULL, 1, CURRENT_TIMESTAMP)
+                        """
+                    ),
+                    {"device_id": device_id, "owner_user_id": user_id},
+                )
+            return
+
+        existing_by_child = (
+            self.db.execute(
+                text("SELECT id FROM device_bindings WHERE child_id = :child_id"),
+                {"child_id": child_id},
+            )
+            .mappings()
+            .first()
+        )
+
+        if existing_by_device:
+            device_row_id = int(existing_by_device["id"])
+            if existing_by_child and int(existing_by_child["id"]) != device_row_id:
+                # Release child ownership from a different row before assigning to this device.
+                self.db.execute(
+                    text(
+                        """
+                        UPDATE device_bindings
+                        SET child_id = NULL,
+                            status = 0,
+                            unbound_at = CURRENT_TIMESTAMP,
+                            updated_at = CURRENT_TIMESTAMP
+                        WHERE id = :id
+                        """
+                    ),
+                    {"id": existing_by_child["id"]},
+                )
+
+            self.db.execute(
+                text(
+                    """
+                    UPDATE device_bindings
+                    SET owner_user_id = :owner_user_id,
+                        child_id = :child_id,
+                        status = 1,
+                        unbound_at = NULL,
+                        updated_at = CURRENT_TIMESTAMP
+                    WHERE device_id = :device_id
+                    """
+                ),
+                {"owner_user_id": user_id, "child_id": child_id, "device_id": device_id},
+            )
+            return
+
+        if existing_by_child:
+            self.db.execute(
+                text(
+                    """
+                    UPDATE device_bindings
+                    SET device_id = :device_id,
+                        owner_user_id = :owner_user_id,
+                        status = 1,
+                        unbound_at = NULL,
+                        updated_at = CURRENT_TIMESTAMP
+                    WHERE id = :id
+                    """
+                ),
+                {"device_id": device_id, "owner_user_id": user_id, "id": existing_by_child["id"]},
+            )
+            return
+
+        self.db.execute(
+            text(
+                """
+                INSERT INTO device_bindings (device_id, owner_user_id, child_id, status, bound_at)
+                VALUES (:device_id, :owner_user_id, :child_id, 1, CURRENT_TIMESTAMP)
+                """
+            ),
+            {"device_id": device_id, "owner_user_id": user_id, "child_id": child_id},
+        )
+
+    def start_bind(self, user_id: int, device_id: str, child_id: Optional[int]) -> str:
         bind_token = str(uuid.uuid4())
         expires_at = datetime.utcnow() + timedelta(minutes=10)
 
@@ -46,106 +212,25 @@ class BindingDAO(BaseDAO):
             .first()
         )
 
-    def confirm_bind(self, session_id: int, device_id: str, child_id: int, user_id: int) -> None:
+    def confirm_bind(self, session_id: int, device_id: str, child_id: Optional[int], user_id: int) -> None:
+        if child_id is not None:
+            self._upsert_parent_child_relation(user_id=user_id, child_id=child_id)
+
         self.db.execute(
             text("UPDATE device_bind_sessions SET status = 2, confirmed_at = CURRENT_TIMESTAMP WHERE id = :id"),
             {"id": session_id},
         )
 
-        existing = self.db.execute(
-            text("SELECT id FROM device_bindings WHERE device_id = :device_id OR child_id = :child_id"),
-            {"device_id": device_id, "child_id": child_id},
-        ).scalar_one_or_none()
-
-        if existing:
-            self.db.execute(
-                text(
-                    "UPDATE device_bindings SET child_id = :child_id, status = 1, unbound_at = NULL WHERE device_id = :device_id"
-                ),
-                {"device_id": device_id, "child_id": child_id},
-            )
-        else:
-            self.db.execute(
-                text(
-                    "INSERT INTO device_bindings (device_id, child_id, status, bound_at) VALUES (:device_id, :child_id, 1, CURRENT_TIMESTAMP)"
-                ),
-                {"device_id": device_id, "child_id": child_id},
-            )
-
-        self.db.execute(
-            text(
-                "INSERT INTO device_bind_history (device_id, child_id, bound_by_user_id, bind_source, bound_at) VALUES (:device_id, :child_id, :user_id, 1, CURRENT_TIMESTAMP)"
-            ),
-            {"device_id": device_id, "child_id": child_id, "user_id": user_id},
-        )
+        self._bind_device(device_id=device_id, user_id=user_id, child_id=child_id)
+        self._insert_bind_history(device_id=device_id, child_id=child_id, user_id=user_id, bind_source=1)
         self.commit()
 
-    def direct_bind(self, device_id: str, child_id: int, user_id: int) -> None:
-        # Check if binding exists for this device_id
-        existing_by_device = (
-            self.db.execute(
-                text("SELECT id FROM device_bindings WHERE device_id = :device_id"),
-                {"device_id": device_id},
-            ).fetchone()
-        )
+    def direct_bind(self, device_id: str, child_id: Optional[int], user_id: int) -> None:
+        if child_id is not None:
+            self._upsert_parent_child_relation(user_id=user_id, child_id=child_id)
 
-        # Check if this child is already bound to a different device
-        existing_by_child = (
-            self.db.execute(
-                text("SELECT id FROM device_bindings WHERE child_id = :child_id AND status = 1"),
-                {"child_id": child_id},
-            ).fetchone()
-        )
-
-        if existing_by_device:
-            # Update existing binding for this device
-            self.db.execute(
-                text(
-                    "UPDATE device_bindings SET child_id = :child_id, status = 1, unbound_at = NULL WHERE device_id = :device_id"
-                ),
-                {"device_id": device_id, "child_id": child_id},
-            )
-            self.db.execute(
-                text(
-                    "INSERT INTO device_bind_history (device_id, child_id, bound_by_user_id, bind_source, bound_at) VALUES (:device_id, :child_id, :user_id, 2, CURRENT_TIMESTAMP)"
-                ),
-                {"device_id": device_id, "child_id": child_id, "user_id": user_id},
-            )
-            self.commit()
-            return
-        elif existing_by_child:
-            # Child already bound to another device - update that binding
-            self.db.execute(
-                text(
-                    "UPDATE device_bindings SET device_id = :device_id, status = 1, unbound_at = NULL WHERE child_id = :child_id AND status = 1"
-                ),
-                {"device_id": device_id, "child_id": child_id},
-            )
-            # Skip INSERT since we updated
-            self.db.execute(
-                text(
-                    "INSERT INTO device_bind_history (device_id, child_id, bound_by_user_id, bind_source, bound_at) VALUES (:device_id, :child_id, :user_id, 2, CURRENT_TIMESTAMP)"
-                ),
-                {"device_id": device_id, "child_id": child_id, "user_id": user_id},
-            )
-            self.commit()
-            return
-        else:
-            # Insert new binding
-            self.db.execute(
-                text(
-                    "INSERT INTO device_bindings (device_id, child_id, status, bound_at) VALUES (:device_id, :child_id, 1, CURRENT_TIMESTAMP)"
-                ),
-                {"device_id": device_id, "child_id": child_id},
-            )
-
-        # Add history
-        self.db.execute(
-            text(
-                "INSERT INTO device_bind_history (device_id, child_id, bound_by_user_id, bind_source, bound_at) VALUES (:device_id, :child_id, :user_id, 2, CURRENT_TIMESTAMP)"
-            ),
-            {"device_id": device_id, "child_id": child_id, "user_id": user_id},
-        )
+        self._bind_device(device_id=device_id, user_id=user_id, child_id=child_id)
+        self._insert_bind_history(device_id=device_id, child_id=child_id, user_id=user_id, bind_source=2)
         self.commit()
 
     def get_current_by_user(self, user_id: int) -> Optional[Mapping]:
@@ -153,10 +238,11 @@ class BindingDAO(BaseDAO):
             self.db.execute(
                 text(
                     """
-                    SELECT b.* FROM device_bindings b
-                    JOIN children c ON b.child_id = c.child_id
-                    WHERE c.parent_user_id = :user_id AND b.status = 1
-                    ORDER BY b.bound_at DESC
+                    SELECT *
+                    FROM device_bindings
+                    WHERE owner_user_id = :user_id
+                      AND status = 1
+                    ORDER BY bound_at DESC
                     LIMIT 1
                     """
                 ),
@@ -171,9 +257,11 @@ class BindingDAO(BaseDAO):
             self.db.execute(
                 text(
                     """
-                    SELECT b.* FROM device_bindings b
-                    JOIN children c ON b.child_id = c.child_id
-                    WHERE b.device_id = :device_id AND c.parent_user_id = :user_id AND b.status = 1
+                    SELECT *
+                    FROM device_bindings
+                    WHERE device_id = :device_id
+                      AND owner_user_id = :user_id
+                      AND status = 1
                     """
                 ),
                 {"device_id": device_id, "user_id": user_id},
@@ -182,6 +270,17 @@ class BindingDAO(BaseDAO):
             .first()
         )
 
+    def set_binding_child(self, device_id: str, child_id: int, user_id: int) -> bool:
+        row = self.get_by_device(device_id=device_id, user_id=user_id)
+        if not row:
+            return False
+
+        self._upsert_parent_child_relation(user_id=user_id, child_id=child_id)
+        self._bind_device(device_id=device_id, user_id=user_id, child_id=child_id)
+        self._insert_bind_history(device_id=device_id, child_id=child_id, user_id=user_id, bind_source=3)
+        self.commit()
+        return True
+
     def unbind(self, device_id: str, user_id: int) -> bool:
         row = self.get_by_device(device_id, user_id)
         if not row:
@@ -223,4 +322,4 @@ class BindingDAO(BaseDAO):
             .mappings()
             .all()
         )
-        return rows
+        return rows

mini-program/app/models/entities.py

@@ -15,6 +15,7 @@ from sqlalchemy import (
     Text,
     Time,
     UniqueConstraint,
+    text,
 )
 from sqlalchemy.orm import Mapped, mapped_column
 
@@ -31,24 +32,20 @@ class Parent(Base):
     avatar_url: Mapped[Optional[str]] = mapped_column(String(255))
     phone: Mapped[Optional[str]] = mapped_column(String(20))
     status: Mapped[int] = mapped_column(Integer, server_default="1")
-    created_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default="CURRENT_TIMESTAMP")
-    updated_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default="CURRENT_TIMESTAMP")
+    created_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"))
+    updated_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"))
 
 
 class Child(Base):
     __tablename__ = "children"
-    __table_args__ = (
-        Index("idx_child_parent_user_id", "parent_user_id"),
-    )
 
     child_id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
-    parent_user_id: Mapped[int] = mapped_column(Integer, nullable=False)
     child_name: Mapped[str] = mapped_column(String(32), nullable=False)
     child_gender: Mapped[int] = mapped_column(Integer, server_default="2")
     child_birthday: Mapped[Optional[date]] = mapped_column(Date)
     status: Mapped[int] = mapped_column(Integer, server_default="1")
-    created_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default="CURRENT_TIMESTAMP")
-    updated_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default="CURRENT_TIMESTAMP")
+    created_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"))
+    updated_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"))
 
 
 class ParentChildRelation(Base):
@@ -65,24 +62,27 @@ class ParentChildRelation(Base):
     relation_type: Mapped[int] = mapped_column(Integer, server_default="9")
     is_primary: Mapped[bool] = mapped_column(Boolean, server_default="0")
     status: Mapped[int] = mapped_column(Integer, server_default="1")
-    created_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default="CURRENT_TIMESTAMP")
-    updated_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default="CURRENT_TIMESTAMP")
+    created_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"))
+    updated_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"))
 
 
 class DeviceBinding(Base):
     __tablename__ = "device_bindings"
     __table_args__ = (
         UniqueConstraint("device_id", name="uq_device_binding_device"),
+        UniqueConstraint("child_id", name="uq_device_binding_child"),
+        Index("idx_device_bindings_owner_user_id", "owner_user_id"),
     )
 
     id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
     device_id: Mapped[str] = mapped_column(String(64), nullable=False, unique=True)
-    child_id: Mapped[int] = mapped_column(Integer, nullable=False)
+    owner_user_id: Mapped[int] = mapped_column(Integer, nullable=False)
+    child_id: Mapped[Optional[int]] = mapped_column(Integer)
     status: Mapped[int] = mapped_column(Integer, server_default="1")
     bound_at: Mapped[datetime] = mapped_column(DateTime, nullable=False)
     unbound_at: Mapped[Optional[datetime]] = mapped_column(DateTime)
-    created_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default="CURRENT_TIMESTAMP")
-    updated_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default="CURRENT_TIMESTAMP")
+    created_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"))
+    updated_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"))
 
 
 class DeviceBindSession(Base):
@@ -101,8 +101,8 @@ class DeviceBindSession(Base):
     status: Mapped[int] = mapped_column(Integer, server_default="1")
     confirmed_at: Mapped[Optional[datetime]] = mapped_column(DateTime)
     consumed_at: Mapped[Optional[datetime]] = mapped_column(DateTime)
-    created_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default="CURRENT_TIMESTAMP")
-    updated_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default="CURRENT_TIMESTAMP")
+    created_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"))
+    updated_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"))
 
 
 class DeviceBindHistory(Base):
@@ -110,14 +110,14 @@ class DeviceBindHistory(Base):
 
     id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
     device_id: Mapped[str] = mapped_column(String(64), nullable=False)
-    child_id: Mapped[int] = mapped_column(Integer, nullable=False)
+    child_id: Mapped[Optional[int]] = mapped_column(Integer)
     bound_by_user_id: Mapped[int] = mapped_column(Integer, nullable=False)
     unbound_by_user_id: Mapped[Optional[int]] = mapped_column(Integer)
     bind_source: Mapped[int] = mapped_column(Integer, server_default="1")
     bound_at: Mapped[datetime] = mapped_column(DateTime, nullable=False)
     unbound_at: Mapped[Optional[datetime]] = mapped_column(DateTime)
     unbind_reason: Mapped[Optional[str]] = mapped_column(String(191))
-    created_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default="CURRENT_TIMESTAMP")
+    created_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"))
 
 
 class Card(Base):
@@ -129,8 +129,8 @@ class Card(Base):
     card_name: Mapped[Optional[str]] = mapped_column(String(64))
     status: Mapped[int] = mapped_column(Integer, server_default="0")
     total_swaps: Mapped[int] = mapped_column(Integer, server_default="0")
-    created_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default="CURRENT_TIMESTAMP")
-    updated_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default="CURRENT_TIMESTAMP")
+    created_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"))
+    updated_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"))
 
 
 class DeviceSetting(Base):
@@ -141,14 +141,15 @@ class DeviceSetting(Base):
     sleep_mode: Mapped[int] = mapped_column(Integer, server_default="0")
     disable_time_start: Mapped[Optional[time]] = mapped_column(Time)
     disable_time_end: Mapped[Optional[time]] = mapped_column(Time)
-    timezone: Mapped[str] = mapped_column(String(32), server_default="'Asia/Shanghai'")
+    timezone: Mapped[str] = mapped_column(String(32), server_default=text("'Asia/Shanghai'"))
     volume: Mapped[Optional[int]] = mapped_column(Integer)
     brightness: Mapped[Optional[int]] = mapped_column(Integer)
     disable_weekdays: Mapped[Optional[str]] = mapped_column(String(32))
-    created_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default="CURRENT_TIMESTAMP")
-    updated_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default="CURRENT_TIMESTAMP")
-    updated_at: Mapped[datetime] = mapped_column(
-        DateTime, default=datetime.utcnow, onupdate=datetime.utcnow
+    created_at: Mapped[Optional[datetime]] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"))
+    updated_at: Mapped[Optional[datetime]] = mapped_column(
+        DateTime,
+        server_default=text("CURRENT_TIMESTAMP"),
+        onupdate=datetime.utcnow,
     )
 
 
@@ -255,4 +256,4 @@ class ChildLocationHistory(Base):
     battery_pct: Mapped[Optional[int]] = mapped_column(Integer)
     device_time: Mapped[datetime] = mapped_column(DateTime, nullable=False)
     server_time: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)
-    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)
+    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)

mini-program/app/routers/bindings.py

@@ -1,4 +1,5 @@
 import logging
+from datetime import datetime
 
 from fastapi import APIRouter, Depends, HTTPException, Request, status
 from pydantic import BaseModel
@@ -19,7 +20,7 @@ logger = logging.getLogger("app.bindings")
 
 class BindStartRequest(BaseModel):
     device_id: str
-    child_id: int
+    child_id: int | None = None
 
 
 class BindStartResponse(BaseModel):
@@ -34,21 +35,21 @@ class BindConfirmRequest(BaseModel):
 
 class BindConfirmResponse(BaseModel):
     device_id: str
-    child_id: int
+    child_id: int | None
 
 
 class BindingGetResponse(BaseModel):
     device_id: str
-    child_id: int
+    child_id: int | None
     status: int
-    bound_at: str
+    bound_at: datetime
 
 
 class BindHistoryItem(BaseModel):
     device_id: str
-    child_id: int
-    bound_at: str
-    unbound_at: str | None
+    child_id: int | None
+    bound_at: datetime
+    unbound_at: datetime | None
 
 
 class BindHistoryResponse(BaseModel):
@@ -86,11 +87,15 @@ def confirm_bind(
 
 class DirectBindRequest(BaseModel):
     device_id: str
-    child_id: int
+    child_id: int | None = None
 
 
 class DirectBindResponse(BaseModel):
     device_id: str
+    child_id: int | None
+
+
+class BindSetChildRequest(BaseModel):
     child_id: int
 
 
@@ -106,6 +111,22 @@ def direct_bind(
     return DirectBindResponse(**result)
 
 
+@router.patch("/{device_id}/child", response_model=DirectBindResponse)
+def set_binding_child(
+    device_id: str,
+    payload: BindSetChildRequest,
+    request: Request,
+    current_user_id: int = Depends(get_current_user_id),
+    db=Depends(get_db_session),
+) -> DirectBindResponse:
+    service = BindingService(db)
+    try:
+        result = service.set_binding_child(device_id=device_id, child_id=payload.child_id, user_id=current_user_id)
+    except ValueError as e:
+        raise HTTPException(status_code=404, detail=str(e))
+    return DirectBindResponse(**result)
+
+
 @router.get("/current", response_model=BindingGetResponse)
 def get_current_binding(
     request: Request,
@@ -154,11 +175,9 @@ def get_bind_history(
     current_user_id: int = Depends(get_current_user_id),
     db=Depends(get_db_session),
 ) -> BindHistoryResponse:
-    from datetime import datetime
-
     cursor_dt = datetime.fromisoformat(cursor) if cursor else None
     service = BindingService(db)
     rows, has_more = service.list_history(device_id, limit, cursor_dt)
     next_cursor = rows[-1]["bound_at"].isoformat() if has_more and rows else None
     items = [BindHistoryItem(**row) for row in rows]
-    return BindHistoryResponse(items=items, total=len(items), next_cursor=next_cursor)
+    return BindHistoryResponse(items=items, total=len(items), next_cursor=next_cursor)

mini-program/app/service/binding.py

@@ -9,7 +9,7 @@ class BindingService:
     def __init__(self, db):
         self.dao = BindingDAO(db)
 
-    def start_bind(self, user_id: int, device_id: str, child_id: int) -> tuple[str, datetime]:
+    def start_bind(self, user_id: int, device_id: str, child_id: int | None = None) -> tuple[str, datetime]:
         bind_token = self.dao.start_bind(user_id, device_id, child_id)
         return bind_token, datetime.utcnow()
 
@@ -31,10 +31,16 @@ class BindingService:
     def get_current_binding(self, user_id: int) -> Optional[Mapping]:
         return self.dao.get_current_by_user(user_id)
 
-    def direct_bind(self, device_id: str, child_id: int, user_id: int) -> Mapping:
+    def direct_bind(self, device_id: str, child_id: int | None, user_id: int) -> Mapping:
         self.dao.direct_bind(device_id, child_id, user_id)
         return {"device_id": device_id, "child_id": child_id}
 
+    def set_binding_child(self, device_id: str, child_id: int, user_id: int) -> Mapping:
+        ok = self.dao.set_binding_child(device_id=device_id, child_id=child_id, user_id=user_id)
+        if not ok:
+            raise ValueError("binding not found")
+        return {"device_id": device_id, "child_id": child_id}
+
     def unbind(self, device_id: str, user_id: int) -> bool:
         return self.dao.unbind(device_id, user_id)
 
@@ -42,4 +48,4 @@ class BindingService:
         rows = self.dao.list_history(device_id, limit, cursor)
         has_more = len(rows) > limit
         rows = rows[:limit]
-        return rows, has_more
+        return rows, has_more

mini-program/database/sql/003_new_tables.sql

@@ -48,7 +48,8 @@ CREATE TABLE IF NOT EXISTS parent_child_relations (
 CREATE TABLE IF NOT EXISTS device_bindings (
     id BIGINT PRIMARY KEY AUTO_INCREMENT,
     device_id VARCHAR(64) NOT NULL,
-    child_id BIGINT NOT NULL,
+    owner_user_id BIGINT NOT NULL,
+    child_id BIGINT,
     status TINYINT NOT NULL DEFAULT 1,
     bound_at DATETIME NOT NULL,
     unbound_at DATETIME,
@@ -58,6 +59,8 @@ CREATE TABLE IF NOT EXISTS device_bindings (
     UNIQUE (child_id)
 );
 
+CREATE INDEX IF NOT EXISTS idx_device_bindings_owner_user_id ON device_bindings(owner_user_id);
+
 -- device_bind_sessions table
 CREATE TABLE IF NOT EXISTS device_bind_sessions (
     id BIGINT PRIMARY KEY AUTO_INCREMENT,
@@ -81,7 +84,7 @@ CREATE TABLE IF NOT EXISTS device_bind_sessions (
 CREATE TABLE IF NOT EXISTS device_bind_history (
     id BIGINT PRIMARY KEY AUTO_INCREMENT,
     device_id VARCHAR(64) NOT NULL,
-    child_id BIGINT NOT NULL,
+    child_id BIGINT,
     bound_by_user_id BIGINT NOT NULL,
     unbound_by_user_id BIGINT,
     bind_source TINYINT NOT NULL DEFAULT 1,
@@ -211,4 +214,4 @@ CREATE TABLE IF NOT EXISTS child_location_history (
     created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
 );
 
-CREATE INDEX IF NOT EXISTS idx_child_loc_hist_child ON child_location_history(child_id, created_at);
+CREATE INDEX IF NOT EXISTS idx_child_loc_hist_child ON child_location_history(child_id, created_at);

mini-program/database/sql/004_device_bindings_owner_user_migration.sql

@@ -0,0 +1,46 @@
+-- Migration: support "bind device first, then set child profile"
+-- Target: MySQL 8.x
+
+-- 1) Add owner_user_id on device_bindings.
+ALTER TABLE device_bindings
+    ADD COLUMN owner_user_id BIGINT NULL AFTER device_id;
+
+-- 2) Backfill owner_user_id from active parent-child relation (prefer primary relation).
+UPDATE device_bindings b
+SET owner_user_id = (
+    SELECT r.user_id
+    FROM parent_child_relations r
+    WHERE r.child_id = b.child_id
+      AND r.status = 1
+    ORDER BY r.is_primary DESC, r.id ASC
+    LIMIT 1
+)
+WHERE b.owner_user_id IS NULL;
+
+-- 3) Fallback backfill from latest bind history.
+UPDATE device_bindings b
+SET owner_user_id = (
+    SELECT h.bound_by_user_id
+    FROM device_bind_history h
+    WHERE h.device_id = b.device_id
+    ORDER BY h.bound_at DESC, h.id DESC
+    LIMIT 1
+)
+WHERE b.owner_user_id IS NULL;
+
+-- 4) Ensure no NULL owner before setting NOT NULL.
+-- If this query returns rows, handle manually before continuing:
+-- SELECT id, device_id, child_id FROM device_bindings WHERE owner_user_id IS NULL;
+
+-- 5) Make schema changes for new flow.
+ALTER TABLE device_bindings
+    MODIFY COLUMN owner_user_id BIGINT NOT NULL;
+
+ALTER TABLE device_bindings
+    MODIFY COLUMN child_id BIGINT NULL;
+
+ALTER TABLE device_bindings
+    ADD INDEX idx_device_bindings_owner_user_id (owner_user_id);
+
+ALTER TABLE device_bind_history
+    MODIFY COLUMN child_id BIGINT NULL;

mini-program/tests/test_dao.py

@@ -77,9 +77,217 @@ def test_binding_dao():
     assert len(token) == 36
 
 
+def test_confirm_bind_upserts_parent_child_relation():
+    """Confirm bind should create parent-child relation when missing."""
+    from sqlalchemy import create_engine, text
+    from sqlalchemy.orm import sessionmaker
+    from app.models import Base
+    from app.dao.binding import BindingDAO
+
+    engine = create_engine("sqlite:///:memory:", echo=False)
+    Base.metadata.create_all(bind=engine)
+    Session = sessionmaker(bind=engine)
+    db = Session()
+
+    db.execute(text("INSERT INTO parents (openid, status) VALUES ('p_bind_confirm', 1)"))
+    db.execute(text("INSERT INTO children (child_name, child_gender, status) VALUES ('Kid Confirm', 2, 1)"))
+    db.commit()
+
+    user_id = int(db.execute(text("SELECT user_id FROM parents WHERE openid = 'p_bind_confirm'")).scalar_one())
+    child_id = int(
+        db.execute(text("SELECT child_id FROM children WHERE child_name = 'Kid Confirm'")).scalar_one()
+    )
+
+    dao = BindingDAO(db)
+    token = dao.start_bind(user_id, "device_confirm_001", child_id)
+    session = dao.get_session(token, user_id)
+    assert session is not None
+
+    dao.confirm_bind(int(session["id"]), "device_confirm_001", child_id, user_id)
+
+    relation = db.execute(
+        text(
+            """
+            SELECT status
+            FROM parent_child_relations
+            WHERE user_id = :user_id AND child_id = :child_id
+            """
+        ),
+        {"user_id": user_id, "child_id": child_id},
+    ).scalar_one_or_none()
+    assert relation == 1
+
+
+def test_direct_bind_reactivates_parent_child_relation():
+    """Direct bind should reactivate an existing disabled parent-child relation."""
+    from sqlalchemy import create_engine, text
+    from sqlalchemy.orm import sessionmaker
+    from app.models import Base
+    from app.dao.binding import BindingDAO
+
+    engine = create_engine("sqlite:///:memory:", echo=False)
+    Base.metadata.create_all(bind=engine)
+    Session = sessionmaker(bind=engine)
+    db = Session()
+
+    db.execute(text("INSERT INTO parents (openid, status) VALUES ('p_bind_direct', 1)"))
+    db.execute(text("INSERT INTO children (child_name, child_gender, status) VALUES ('Kid Direct', 2, 1)"))
+    db.commit()
+
+    user_id = int(db.execute(text("SELECT user_id FROM parents WHERE openid = 'p_bind_direct'")).scalar_one())
+    child_id = int(db.execute(text("SELECT child_id FROM children WHERE child_name = 'Kid Direct'")).scalar_one())
+
+    db.execute(
+        text(
+            """
+            INSERT INTO parent_child_relations (user_id, child_id, relation_type, is_primary, status)
+            VALUES (:user_id, :child_id, 9, 0, 0)
+            """
+        ),
+        {"user_id": user_id, "child_id": child_id},
+    )
+    db.commit()
+
+    dao = BindingDAO(db)
+    dao.direct_bind("device_direct_001", child_id, user_id)
+
+    relation = db.execute(
+        text(
+            """
+            SELECT status
+            FROM parent_child_relations
+            WHERE user_id = :user_id AND child_id = :child_id
+            """
+        ),
+        {"user_id": user_id, "child_id": child_id},
+    ).scalar_one()
+    assert relation == 1
+
+
+def test_direct_bind_without_child_then_set_child():
+    """Direct bind should support empty child first and assign child later."""
+    from sqlalchemy import create_engine, text
+    from sqlalchemy.orm import sessionmaker
+    from app.models import Base
+    from app.dao.binding import BindingDAO
+
+    engine = create_engine("sqlite:///:memory:", echo=False)
+    Base.metadata.create_all(bind=engine)
+    Session = sessionmaker(bind=engine)
+    db = Session()
+
+    db.execute(text("INSERT INTO parents (openid, status) VALUES ('p_bind_later', 1)"))
+    db.execute(text("INSERT INTO children (child_name, child_gender, status) VALUES ('Kid Later', 2, 1)"))
+    db.commit()
+
+    user_id = int(db.execute(text("SELECT user_id FROM parents WHERE openid = 'p_bind_later'")).scalar_one())
+    child_id = int(db.execute(text("SELECT child_id FROM children WHERE child_name = 'Kid Later'")).scalar_one())
+
+    dao = BindingDAO(db)
+    dao.direct_bind("device_later_001", None, user_id)
+
+    current = dao.get_current_by_user(user_id)
+    assert current is not None
+    assert current["device_id"] == "device_later_001"
+    assert current["child_id"] is None
+
+    changed = dao.set_binding_child("device_later_001", child_id, user_id)
+    assert changed is True
+
+    current = dao.get_current_by_user(user_id)
+    assert current is not None
+    assert int(current["child_id"]) == child_id
+
+    relation = db.execute(
+        text(
+            """
+            SELECT status
+            FROM parent_child_relations
+            WHERE user_id = :user_id AND child_id = :child_id
+            """
+        ),
+        {"user_id": user_id, "child_id": child_id},
+    ).scalar_one()
+    assert relation == 1
+
+
+def test_update_my_relation_switches_primary():
+    """Relation update should switch primary parent on the same child."""
+    from sqlalchemy import create_engine, text
+    from sqlalchemy.orm import sessionmaker
+    from app.models import Base
+    from app.dao.relation import RelationDAO
+
+    engine = create_engine("sqlite:///:memory:", echo=False)
+    Base.metadata.create_all(bind=engine)
+    Session = sessionmaker(bind=engine)
+    db = Session()
+
+    db.execute(text("INSERT INTO parents (openid, status) VALUES ('p_relation_1', 1)"))
+    db.execute(text("INSERT INTO parents (openid, status) VALUES ('p_relation_2', 1)"))
+    db.execute(text("INSERT INTO children (child_name, child_gender, status) VALUES ('Kid Relation', 2, 1)"))
+    db.commit()
+
+    user_id_1 = int(db.execute(text("SELECT user_id FROM parents WHERE openid = 'p_relation_1'")).scalar_one())
+    user_id_2 = int(db.execute(text("SELECT user_id FROM parents WHERE openid = 'p_relation_2'")).scalar_one())
+    child_id = int(db.execute(text("SELECT child_id FROM children WHERE child_name = 'Kid Relation'")).scalar_one())
+
+    db.execute(
+        text(
+            """
+            INSERT INTO parent_child_relations (user_id, child_id, relation_type, is_primary, status)
+            VALUES (:user_id, :child_id, :relation_type, :is_primary, 1)
+            """
+        ),
+        {"user_id": user_id_1, "child_id": child_id, "relation_type": 9, "is_primary": 0},
+    )
+    db.execute(
+        text(
+            """
+            INSERT INTO parent_child_relations (user_id, child_id, relation_type, is_primary, status)
+            VALUES (:user_id, :child_id, :relation_type, :is_primary, 1)
+            """
+        ),
+        {"user_id": user_id_2, "child_id": child_id, "relation_type": 9, "is_primary": 1},
+    )
+    db.commit()
+
+    dao = RelationDAO(db)
+    updated = dao.update_my_relation(
+        child_id=child_id,
+        user_id=user_id_1,
+        relation_type=2,
+        is_primary=True,
+    )
+
+    assert updated is not None
+    assert int(updated["relation_type"]) == 2
+    assert int(updated["is_primary"]) == 1
+    assert int(updated["status"]) == 1
+
+    other_primary = int(
+        db.execute(
+            text(
+                """
+                SELECT is_primary
+                FROM parent_child_relations
+                WHERE child_id = :child_id
+                  AND user_id = :user_id
+                """
+            ),
+            {"child_id": child_id, "user_id": user_id_2},
+        ).scalar_one()
+    )
+    assert other_primary == 0
+
+
 if __name__ == "__main__":
     test_sqlite_connection()
     test_parent_dao()
     test_child_dao()
     test_binding_dao()
-    print("All DAO tests passed!")
+    test_confirm_bind_upserts_parent_child_relation()
+    test_direct_bind_reactivates_parent_child_relation()
+    test_direct_bind_without_child_then_set_child()
+    test_update_my_relation_switches_primary()
+    print("All DAO tests passed!")