Laravel将ID从一个表插入另一个表

Question

I have two tables categories and product_categories .

categories has id , name and product_categories has category_id . How do I fetch id from categories and put that value to category_id ?

I tried:

Route::get('/categories/create', function() {
    $categories = [
        'Hardwares', 
        'Buldings',
        'Properties',
    ];

    foreach($categories as $category) {
        $productCategories = new ProductCategory;
        $categories = new Category;
        $categories->name = $category;
        $productCategories->category_id = $categories->id;
        $categories->save();
        $productCategories->save();
    }
}); 

Is it possible via one to one relationship? I just tried this in `ProductCategory.php':

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

Answer 1

save the category before using its attribute ..

foreach($categories as $category) {
    $categories = new Category;
    $categories->name = $category;
    $categories->save();

    $productCategories = new ProductCategory;
    $productCategories ->category_id = $categories->id;
    $productCategories->save();
}