Laravel 关系很深答案

【问题标题】：Laravel relations deepLaravel 关系很深
【发布时间】：2017-08-02 10:36:53
【问题描述】：

我正在使用 laravel 5.3。我有 Promotion 属于 Device 和 Device hasMany emails。谁能给我建议。我如何才能在促销查询中连接到具有此促销的设备的所有电子邮件？

目前我正在尝试这样的事情

在促销模式中

public function devicesWithEmails()
{
    return $this->belongsTo(Device::class)->with('Emails');
}

获取查询看起来像（在促销中）

public function search($data)
{
    $perPage = empty($data['perPage']) ? 10 : $data['perPage'];
    $sortField = empty($data['sortField']) ? 'id' : $data['sortField'];
    $keyword = empty($data['keyword']) ? null : $data['keyword'];

    $promotions = Promotion::whereHas('email', function ($query) use ($keyword) {
        if ( ! empty($keyword)) {
            $query->where('email', 'like', "%{$keyword}%");
        }
    })
    ->orWhere('promo_code', 'like', "%{$keyword}%")
    ->with('devicesWithEmails')
    ->orderBy($sortField)
    ->paginate($perPage);

    return $promotions->toArray();
}

设备型号

public function emails()
{
    return $this->belongsToMany(Email::class, 'emails_devices');
}

电子邮件模型

public function devices()
{
    return $this->belongsToMany(Device::class, 'emails_devices');
}

推广模式

public function device()
{
    return $this->belongsTo(Device::class);
}

表结构是

    CREATE TABLE `devices` (
        `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
        `created_at` TIMESTAMP NULL DEFAULT NULL,
        `updated_at` TIMESTAMP NULL DEFAULT NULL,
        `apptype` VARCHAR(255) NULL DEFAULT NULL COLLATE 'utf8_unicode_ci',
        `oid_id` VARCHAR(255) NULL DEFAULT NULL COLLATE 'utf8_unicode_ci',
        `lang` VARCHAR(255) NULL DEFAULT NULL COLLATE 'utf8_unicode_ci',
        `referrer` VARCHAR(255) NULL DEFAULT NULL COLLATE 'utf8_unicode_ci',
        `app_version` VARCHAR(255) NULL DEFAULT NULL COLLATE 'utf8_unicode_ci',
        `mobiledeviceid` VARCHAR(255) NOT NULL COLLATE 'utf8_unicode_ci',
        `name` VARCHAR(255) NOT NULL COLLATE 'utf8_unicode_ci',
        `is_paid` TINYINT(1) NULL DEFAULT NULL,
        `status` TINYINT(1) NULL DEFAULT NULL,
        `is_internal_user` TINYINT(1) NULL DEFAULT NULL,
        `paid_date` DATE NULL DEFAULT NULL,
        `paid_date_end` DATE NULL DEFAULT NULL,
        PRIMARY KEY (`id`)
    )
    COLLATE='utf8_unicode_ci'
    ENGINE=InnoDB;

CREATE TABLE `emails` (
    `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
    `created_at` TIMESTAMP NULL DEFAULT NULL,
    `updated_at` TIMESTAMP NULL DEFAULT NULL,
    `status` INT(11) NOT NULL DEFAULT '1',
    `email` VARCHAR(255) NOT NULL COLLATE 'utf8_unicode_ci',
    `client_type` VARCHAR(255) NOT NULL COLLATE 'utf8_unicode_ci',
    PRIMARY KEY (`id`)
)
COLLATE='utf8_unicode_ci'
ENGINE=InnoDB;

CREATE TABLE `emails_devices` (
    `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
    `created_at` TIMESTAMP NULL DEFAULT NULL,
    `updated_at` TIMESTAMP NULL DEFAULT NULL,
    `email_id` INT(10) UNSIGNED NOT NULL,
    `device_id` INT(10) UNSIGNED NOT NULL,
    PRIMARY KEY (`id`),
    INDEX `emails_devices_email_id_foreign` (`email_id`),
    INDEX `emails_devices_device_id_foreign` (`device_id`),
    CONSTRAINT `emails_devices_device_id_foreign` FOREIGN KEY (`device_id`) REFERENCES `devices` (`id`) ON DELETE CASCADE,
    CONSTRAINT `emails_devices_email_id_foreign` FOREIGN KEY (`email_id`) REFERENCES `emails` (`id`) ON DELETE CASCADE
)
COLLATE='utf8_unicode_ci'
ENGINE=InnoDB;

CREATE TABLE `promotions` (
    `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
    `created_at` TIMESTAMP NULL DEFAULT NULL,
    `updated_at` TIMESTAMP NULL DEFAULT NULL,
    `status` INT(11) NULL DEFAULT NULL,
    `batch_name` VARCHAR(255) NULL DEFAULT NULL COLLATE 'utf8_unicode_ci',
    `promo_code` VARCHAR(255) NOT NULL COLLATE 'utf8_unicode_ci',
    `validity` TIMESTAMP NULL DEFAULT NULL,
    `date` TIMESTAMP NULL DEFAULT NULL,
    `device_id` INT(10) UNSIGNED NULL DEFAULT NULL,
    `email_id` INT(10) UNSIGNED NULL DEFAULT NULL,
    `used_date` DATE NULL DEFAULT NULL,
    PRIMARY KEY (`id`),
    INDEX `promotions_device_id_foreign` (`device_id`),
    INDEX `promotions_email_id_foreign` (`email_id`),
    INDEX `promo_code_index` (`promo_code`),
    CONSTRAINT `promotions_device_id_foreign` FOREIGN KEY (`device_id`) REFERENCES `devices` (`id`) ON DELETE CASCADE,
    CONSTRAINT `promotions_email_id_foreign` FOREIGN KEY (`email_id`) REFERENCES `emails` (`id`) ON DELETE CASCADE
)
COLLATE='utf8_unicode_ci'
ENGINE=InnoDB;

不幸的是 devicesWithEmails 总是返回 null。

【问题讨论】：

到目前为止你有什么尝试？
你可以添加一些你尝试的代码
我用代码示例更新了问题。感谢关注！
这个查询有什么问题？它给出错误或给出错误的输出？因为使用->with('devicesWithEmails')，您可以让所有设备连接到 Promotion
恐怕返回null

标签： laravel eloquent

【解决方案1】：

找到简单的解决方案

只是

public function search($data)
    {
        $perPage = empty($data['perPage']) ? 10 : $data['perPage'];
        $sortField = empty($data['sortField']) ? 'id' : $data['sortField'];
        $keyword = empty($data['keyword']) ? null : $data['keyword'];

        $promotions = Promotion::whereHas('email', function ($query) use ($keyword) {
            if (!empty($keyword)) {
                $query->where('email', 'like', "%{$keyword}%");
            }
        })
            ->orWhere('promo_code', 'like', "%{$keyword}%")
            ->with('device.emails')
            ->orderBy($sortField)
            ->paginate($perPage);

        return $promotions->toArray();
    }

【讨论】：