laravel Eloquent中的模型关联如何使用_Laravel Eloquent模型关联使用教程

// app/Models/User.php
public function profile()
{
    return $this->hasOne(Profile::class);
}

// app/Models/Profile.php
public function user()
{
    return $this->belongsTo(User::class);
}

$user = User::find(1);
echo $user->profile->email;

// app/Models/Post.php
public function comments()
{
    return $this->hasMany(Comment::class);
}

// app/Models/Comment.php
public function post()
{
    return $this->belongsTo(Post::class);
}

$post = Post::find(1);
foreach ($post->comments as $comment) {
    echo $comment->content;
}

// app/Models/User.php
public function roles()
{
    return $this->belongsToMany(Role::class);
}

// app/Models/Role.php
public function users()
{
    return $this->belongsToMany(User::class);
}

$user = User::find(1);
foreach ($user->roles as $role) {
    echo $role->name;
}

// 添加角色
$user->roles()->attach($roleId);

// app/Models/Image.php
public function imageable()
{
    return $this->morphTo();
}

// app/Models/Post.php
public function images()
{
    return $this->morphMany(Image::class, 'imageable');
}

$post = Post::find(1);
foreach ($post->images as $image) {
    echo $image->url;
}