底层执行的 SQL 语句一个 NOT EXISTS 查询: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 select * from `users` where not exists ( select * from `posts` where `users`.`id` = `posts`.`user_id` and `posts`.`deleted_at` is null ) an
...not-null="true" /> --- 对于双向多对多关系...在数据库设计时,需要设计一个中间表 teacher_student ,通过中间表描述学生表和老师表的多对多关系。...--- 1、这里比一对多关联多一个 table 属性,table 指向数据库建立的关联的那张表。 2、Key 中的 column : 关联表中和 student 表发生关系的字...
$foreignKey = null, $ownerKey = null, $relation = null)17//第一个参数为model, 先讲第四个参数,默认为调用belongsTo()的方法名字, 第二个参数默认为第四个参数加上
第二个参数是当前模型类所属表的外键,在本例中是 user_profiles 表的 user_id 字段,拼接规则和 hasOne 那里类似,只不过这里是基于第四个参数关联关系名称 $relation: Copy Highlighter-hljs if(is_null($relation)) {$relation=$this->guessBelongsToRelation(); } ...if(is_null($foreignKey)) {$foreign...
字符串Controller（App\Http\Controller\PostController.php）：要使用where条件访问hasMany关系，可以使用...
默认情况下,Laravel 将根据模型的类名来确定给定模型的关联关系; 你也可以通过将关系名称作为 whereBelongsTo 方法的第二个参数来手动指定关系名称:$posts = Post::whereBelongsTo($user, 'author')->get(); 一对多检索有时一个模型可能有许多相关模型,如果你想很轻松的检索「最新」或「最旧」的相关模型。
1$user->posts()->where('active', 1)->get();But, before diving too deep into using relationships, let's learn how to define each type:One To OneA one-to-one relationship is a very basic relation. For example, a User model might be associated with one Phone. To define this ...
如果需要更多功能,可以使用 whereHas 和orWhereHas 方法将「where」条件放到 has 查询上。这些方法允许你向关联加入自定义约束,比如检查评论内容:use Illuminate\Database\Eloquent\Builder; // 获取至少带有一条评论内容包含 foo% 关键词的文章... $posts = Post::whereHas('comments', function (Builder $query)...
1$comments = Post::find(1)->comments()->where('title', '=', 'foo')->first();Again, you may override the conventional foreign key by passing a second argument to the hasMany method. And, like the hasOne relation, the local column may also be specified:1return $this->hasMany('...
$query->whereIn('email', ['taylor@laravel.com', 'david@laravel.com']); }); } }), Limiting Relation ResultsYou can limit the number of results that are returned when searching the field by defining a relatableSearchResults property on the class of the resource that you are ...