fix: BOM草稿模块缺陷修复（事务回滚 + 外键约束 + 前端状态清理）

inventory-backend/app/models/bom.py

@@ -5,8 +5,18 @@ class BomTable(db.Model):
     __tablename__ = 'bom_table'
 
     id = db.Column(db.Integer, primary_key=True)
-    parent_id = db.Column(db.Integer, db.ForeignKey('material_base.id'), nullable=False, index=True)  # ★ 父子件关联高频列
-    child_id = db.Column(db.Integer, db.ForeignKey('material_base.id'), nullable=False, index=True)    # ★ 子件过滤高频列
+    parent_id = db.Column(
+        db.Integer,
+        db.ForeignKey('material_base.id', ondelete='SET NULL'),
+        nullable=False,
+        index=True
+    )
+    child_id = db.Column(
+        db.Integer,
+        db.ForeignKey('material_base.id', ondelete='SET NULL'),
+        nullable=False,
+        index=True
+    )
 
     bom_no = db.Column(db.String(100), nullable=False, index=True, comment='BOM编号')  # ★ Redis 缓存 Key + 列表查询核心列
     version = db.Column(db.String(50), nullable=False, default='V1.0', index=True, comment='版本')  # ★ 配合 bom_no 做唯一性约束
@@ -24,5 +34,15 @@ class BomTable(db.Model):
     )
 
     # relationships
-    parent = db.relationship('MaterialBase', foreign_keys=[parent_id], backref='bom_parents')
-    child = db.relationship('MaterialBase', foreign_keys=[child_id], backref='bom_children')
+    parent = db.relationship(
+        'MaterialBase',
+        foreign_keys=[parent_id],
+        backref='bom_parents',
+        passive_deletes=True
+    )
+    child = db.relationship(
+        'MaterialBase',
+        foreign_keys=[child_id],
+        backref='bom_children',
+        passive_deletes=True
+    )