鉴于一对一多态关系，无法检索数据

Question

我有一个书籍表和一个图像表，将来我还将有一个博客表。这就是为什么我想在书籍、博客和图像表之间创建多态关系。但我的问题是，当我厌倦了从关系中检索图书图像 url 的数据时，home.blade.php我@foreach得到了以下结果：Call to a member function getImage() on null (View: F:\xampp\htdocs\BookReader\resources\views\Main_pages\includes\Home\new_product.blade.php) 代码如下：home.blade.php@extends('Main_pages.app')@section('title','Home')@section('content')    @include('Main_pages.includes.Home.new_product')    @include('Main_pages.includes.Home.testimonial')    @include('Main_pages.includes.Home.popular_products')    @include('Main_pages.includes.Home.news_letter')    @include('Main_pages.includes.Home.blogs')    @include('Main_pages.includes.Home.quick_view')@endsectionnew_product.blade.php<section class="wn__product__area brown--color pt--80  pb--30"><div class="container">    <div class="row">        <div class="col-lg-12">            <div class="section__title text-center">                <h2 class="title__be--2">New <span class="color--theme">Products</span></h2>                <p>There are many variations of passages of Lorem Ipsum available, but the majority have suffered lebmid alteration in some ledmid form</p>            </div>        </div>    </div>    <!-- Start Single Tab Content -->    <div class="furniture--4 border--round arrows_style owl-carousel owl-theme row mt--50">        @foreach($new_books as $book)        <!-- Start Single Product -->}}        <div class="product product__style--3">            <div class="col-lg-3 col-md-4 col-sm-6 col-12">                <div class="product__thumb">                    <a class="first__img" href="single-product.html"><img src="{{$book->image->getImage()}}" alt="product image"></a>                    <div class="hot__box">                        <span class="hot-label">BEST SALLER</span>                    </div>                </div>

Answer 1

这很明显。有一本没有任何图像的书。将img代码更改为：

@isset ($book->image)

    <img src="{{$book->image->getImage()}}" alt="product image">

@endisset

或使用optional method和Null Coalesce Operator来获得默认图像：

<img src="{{optional($book->image)->getImage() ?? 'default_image_path.png'}}" alt="product image">

或者这个：

@if (isset($book->image))

    <img src="{{$book->image->getImage()}}" alt="product image">

@else

    <img src="default_image_path.png" alt="product image">

@endif

我希望这可以帮助你。