php - Laravel CRUD 删除不适用于外键

Question

我与数据库中的category_id 列有外部关系，但在删除时出现错误。 这是我的删除代码:

  public function destroy($id)
{
    $category = Category::find($id);
    $category->delete();
    Session::flash('success', 'The category was successfully deleted.');
    return redirect()->route('categories.index');
}

我看到的错误是:

SQLSTATE[23000]: Integrity constraint violation: 1451 Cannot delete or update a parent row: a foreign key constraint fails (`fitilicious`.`products`, CONSTRAINT `products_category_id_foreign` FOREIGN KEY (`category_id`) REFERENCES `categories` (`id`)) (SQL: delete from `categories` where `id` = 2)

请帮忙。

Answer 1

我的赌注是将外键设置为 ON DELETE RESTRICT 而不是 CASCADE。

Cannot delete or update a parent row: a foreign key constraint fails (fitilicious.products, CONSTRAINT products_category_id_foreign FOREIGN KEY (category_id) REFERENCES categories (id)) (SQL: delete from categories where id = 2)

这告诉我们表“products”中有一行引用了您尝试删除的类别。

• ON DELETE CASCADE 也会删除该产品。
• ON DELETE RESTRICT 将阻止删除非空类别
• ON DELETE SET NULL 将删除产品表中的类别并将category_id 设置为 NULL

每种都有其用途，但您需要选择您需要的。