[英]How to perform this operation in a view with Query builder and pivot table
我有一个“老师”表和一个“课程”表。 当我处于带有“ foreach”的“老师”视图时,可以访问我的“课程”数据。
@foreach($teacher->courses as $course)
<li>{{ $course->title }}</li>
@endforeach
但是,如果“教师”没有“课程”,我想隐藏该部分。
@if(teacher_has_course)
<section class="My section">
@foreach($teacher->courses as $course)
<li>{{ $course->title }}</li>
@endforeach
</section>
@endif
我不明白这个原则。 你能帮助我吗 ? 谢谢
您可以像这样检查:
@if(!empty($teacher->courses) && count($teacher->courses))
<section class="My section">
@foreach($teacher->courses as $course)
<li>{{ $course->title }}</li>
@endforeach
</section>
@endif
<section class="My section">
@foreach($teacher->courses as $course)
@unless(!$course)
<li>{{ $course->title }}</li>
@endunless
@endforeach
</section>
要么
@unless(!$teacher->courses)
<section class="My section">
@foreach($teacher->courses as $course)
<li>{{ $course->title }}</li>
@endforeach
</section>
@endunless
如果已定义两个表之间的关系,则可以使用->has()
方法。 假设“老师”和“课程”之间存在一对多的关系,那么您可以像这样检查
@if($teacher->has('course'))
// html code that you want to show
@endif
请参阅https://laravel.com/docs/5.4/eloquent-relationships#querying-relationship-existence
希望这可以帮助
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