删除二级分类时，校验是否存在套题

src/main/java/com/project/classicpaper/application/impl/ClassicCategoryApplicationServiceImpl.java

@@ -257,6 +257,14 @@ public class ClassicCategoryApplicationServiceImpl implements ClassicCategoryApp
                 throw new BusinessErrorException("该分类下存在子分类，无法删除");
             }
         }
+        // 如果是二级分类，校验是否存在套题
+        if (Objects.equals(category.getLevel(), 2)) {
+            long paperSetCount = classicPaperSetBaseService.count(
+                    new LambdaQueryWrapper<ClassicPaperSetEntity>().eq(ClassicPaperSetEntity::getClassicCategoryId, id));
+            if (paperSetCount > 0) {
+                throw new BusinessErrorException("该分类下存在套题，无法删除");
+            }
+        }
         classicCategoryBaseService.removeById(id);
         return Result.success("删除成功");
     }