我们链式调用了一个名为with()的新方法。with()方法允许我们将数据从控制器传递到视图。这个方法接受两个参数。第一个参数是将在视图中创建的变量的名称。第二个参数将是该变量的值。 总结一下,我们已经查询了数据库中的所有用户,并将它们作为User对象数组传递给了视图。由于users是with()方法的第一个参数,所以U...
*/ public function user(): BelongsTo { return $this->belongsTo(User::class)->withDefault(function (User $user, Post $post) { $user->name = 'Guest Author'; }); }Querying Belongs To RelationshipsWhen querying for the children of a "belongs to" relationship, you may manually build the...
pieces about your framework – in time, the relationship may just grow intoaLaravel->..., just click on them. They open in new tabs. As expected,Laravelwon byalarge margin once again. 状态模式 行为。 具体状态(Concrete State)角色:实现抽象状态所对应的行为。 其结构图如图1所示。 图1状态模式...
DB::table('merchants')->insert($datas); } } class PhoneTableSeeder extends Seeder { /** * Run the database seeds. * * @return void */ public function run() { $faker = Faker\Factory::create(); $merchant_ids = \App\Merchant::lists('id')->toArray(); $datas = []; foreach ...
然后,在我们的控制器中,我们可以做这个“魔术”:$users=Topic::with('latestPost')->get()->sortByDesc('latestPost.created_at');9.Eloquent::when()——不再有if-else我们中的许多人使用“if-else”编写条件查询,如下所示:if(request('filter_by') =='likes') {$query->where('likes','>',reques...
For example, perhaps you need to insert a new Comment for a Post model. Instead of manually setting the post_id attribute on the Comment, you may insert the Comment directly from the relationship's save method:1$comment = new App\Comment(['message' => 'A new comment.']); 2 3$...
If you want your pivot table to have automatically maintained created_at and updated_at timestamps, use the withTimestamps method on the relationship definition:1return $this->belongsToMany('Role')->withTimestamps();Deleting Records On A Pivot TableTo delete all records on the pivot table ...
5. Avoid N+1 queries by eager loading relationship You might have heard of this tip a million times. So I will keep it as short and simple as possible. Let's assume you have the following scenario 1class PostController extends Controller ...
目录 一、前言 二、实体-关系图(E-R图) 1、实体(Entity): 2、属性(Attribute): 3、关系(Relationship): 4、关系类型 一对一关系 (1 ∶ 1) 一对多关系...(1 ∶ N) 多对多关系 (M ∶ N) 5、ER图中符号的表示 --- 一、前言 系统设计中一个重要的环节就是数据库设计,数据库设计的时候需要先...
The Laravel Framework interacts with the databases using raw SQL, the fluent query builder, and the Eloquent ORM. A model handles the data used by the application. An eloquent relationship helps to link database tables easily. Migration is a special feature used to create a database table. Se...