Laravel Eloquent ORM 指南
Eloquent ORM 模式：模型定义、关系、查询作用域、访问器/修改器和预加载。
1. 模型定义
class Article extends Model
{
use HasFactory, SoftDeletes;
protected $fillable = ['title', 'slug', 'content', 'status', 'author_id'];
protected $hidden = ['deleted_at'];
protected $casts = [
'published_at' => 'datetime',
'metadata' => 'array',
'is_featured' => 'boolean',
];
}2. 关系
class Article extends Model
{
public function author()
{
return $this->belongsTo(User::class, 'author_id');
}
public function comments()
{
return $this->hasMany(Comment::class)->latest();
}
public function tags()
{
return $this->belongsToMany(Tag::class, 'article_tags')
->withTimestamps()
->withPivot('order');
}
}3. 作用域
class Article extends Model
{
public function scopePublished($query)
{
return $query->where('status', 'published');
}
public function scopeByAuthor($query, $authorId)
{
return $query->where('author_id', $authorId);
}
}
$articles = Article::published()->byAuthor(1)->latest()->paginate(15);4. 预加载
$articles = Article::with(['author', 'tags', 'comments.user'])->published()->get();
// 带约束的预加载
$articles = Article::with([
'comments' => fn($q) => $q->where('approved', true)->latest()->take(5),
])->get();
// withCount
$articles = Article::withCount(['comments', 'likes'])->get();
// 访问: $article->comments_count
// 防止 N+1（全局）
Model::preventLazyLoading(! app()->isProduction());