Laravel中的最新和最古老的关系方法

Laravel的雄辩ORM提供了方便的

>和latestOfMany()的方法，用于有效检索关系中最新或最古老的相关模型。 这简化了否则需要复杂排序和过滤的查询。oldestOfMany()>

这些方法在需要跟踪历史数据，显示最新活动或确定初始事件的应用程序中特别有用。

考虑一个方案跟踪用户登录和购买：

这是一个更全面的示例，用于管理客户互动，购买和订阅：

class User extends Model
{
    public function lastLogin(): HasOne
    {
        return $this->hasOne(Login::class)->latestOfMany();
    }

    public function firstPurchase(): HasOne
    {
        return $this->hasOne(Purchase::class)->oldestOfMany();
    }
}

访问此数据很简单：

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\HasOne;

class Customer extends Model
{
    public function lastInteraction(): HasOne
    {
        return $this->hasOne(Interaction::class)->latestOfMany();
    }

    public function largestPurchase(): HasOne
    {
        return $this->hasOne(Purchase::class)->ofMany('total_amount', 'max');
    }

    public function initialSubscription(): HasOne
    {
        return $this->hasOne(Subscription::class)->oldestOfMany('started_at');
    }

    public function activeMembership(): HasOne
    {
        return $this->hasOne(Membership::class)->latestOfMany()->where('status', 'active');
    }
}

>

和

// Retrieve customers with related data
$customers = Customer::with([
    'lastInteraction',
    'largestPurchase',
    'initialSubscription',
    'activeMembership'
])->get();

// Access relationship attributes
foreach ($customers as $customer) {
    echo "Last Contact: " . $customer->lastInteraction->created_at . PHP_EOL;
    echo "Largest Purchase: $" . $customer->largestPurchase->total_amount . PHP_EOL;
}

方法通过将复杂的查询逻辑封装在关系定义中。

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