Laravel 关系找到根父级

Question

我有categories 表结构类似：

id
title
category_id

类别模型关系：

public function categories()
{
    return $this->hasMany(Category::class);
}

public function subcategories()
{
    return $this->categories()->with('subcategories');
}

public function parent()
{
    return $this->belongsTo(Category::class);
}

示例表数据：

{
    "id": 1,
    "title": "Product Categories Group",
    "category_id": null
},
{
    "id": 2,
    "title": "Buy",
    "category_id": 1
},
{
    "id": 3,
    "title": "Sale",
    "category_id": 1
},
{
    "id": 4,
    "title": "Fruits",
    "category_id": 2
},
{
    "id": 5,
    "title": "Apple",
    "category_id": 4
}

在这种情况下，我如何使用 id 检查父类别是 Buy 类别或 Sale。例如如何检查Apple 类别父是Buy 或Sale 类别？

Answer 1

你可以使用while循环，直到找到父级

试试这个

$category = Category::where('title', 'Apple')->firstOrFail();
if (!$category->category_id) {
        $parentCategory = $category;
}
while (isset($category->category_id)) {
    $category = Category::find($category->category_id);
}

return $parentCategory;