Laravel如何通过数据透视表获取相关字段列表

Posted 2023-02-16

【中文标题】Laravel如何通过数据透视表获取相关字段列表

【英文标题】：Laravel how to get list of related fields through pivot table

【发布时间】：2021-06-06 06:11:51

【问题描述】：

我有 4 个表：peoples、company、country 和数据透视表 company_people（因为 peoples 和 Companies 都属于很多），它同时具有 people_id 和 company_id。

在 People 模型中，我有以下功能：

class People extends Model

    // main company (only one)
    public function company()
    
        return $this->belongsTo(Company::class);
    
    // all other companies
    public function companies()
    
        return $this->belongsToMany(Company::class);
    
    public function country()
    
        return $this->belongsTo(Country::class);
    

然后在人员控制器中，我有以下内容，以便准备将所有人员的列表与相关的主要公司名称（只有一个）、国家名称（只有一个）和其他公司显示为名称列表.我可以做前两个，但不能做最后一个。我该怎么做？

$peoples = People::orderBy($sortField,$sortOrder)
    ->with(['companies','company','country'])
    ->get();

foreach ($peoples as $people) 
    $people->company = '['.$people->company->company.']'; // main company name
    $people->country = '['.$people->country->country.']'; // country name
    $people->otherCompanies = ? // list of other company names through pivot table

这里是 4 个表的所有结构：

CREATE TABLE `company_people` (
  `id` bigint NOT NULL,
  `created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  `updated_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  `company_id` bigint UNSIGNED NOT NULL,
  `people_id` bigint UNSIGNED NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;


CREATE TABLE `countries` (
  `id` varchar(4) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT 'AA',
  `created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `updated_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `is_active` int NOT NULL DEFAULT '1',
  `country` varchar(60) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;


CREATE TABLE `peoples` (
  `id` bigint UNSIGNED NOT NULL,
  `created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `updated_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `is_active` int NOT NULL DEFAULT '1',
  `firstname` varchar(120) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '',
  `lastname` varchar(120) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci DEFAULT '',
  `country_id` varchar(4) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT 'ZA',
  `company_id` bigint UNSIGNED DEFAULT '0'
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci PACK_KEYS=0;

ALTER TABLE `company_people`
  ADD PRIMARY KEY (`id`),
  ADD KEY `article_id` (`company_id`),
  ADD KEY `tag_id` (`people_id`);

ALTER TABLE `countries`
  ADD PRIMARY KEY (`id`);

ALTER TABLE `peoples`
  ADD PRIMARY KEY (`id`),
  ADD KEY `country_id` (`country_id`),
  ADD KEY `company_id` (`company_id`);

ALTER TABLE `company_people`
  MODIFY `id` bigint NOT NULL AUTO_INCREMENT;

ALTER TABLE `peoples`
  MODIFY `id` bigint UNSIGNED NOT NULL AUTO_INCREMENT;

ALTER TABLE `peoples`
  ADD CONSTRAINT `peoples-company` FOREIGN KEY (`company_id`) REFERENCES `companies` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
  ADD CONSTRAINT `peoples-country` FOREIGN KEY (`country_id`) REFERENCES `countries` (`id`) ON DELETE RESTRICT ON UPDATE RESTRICT;

ALTER TABLE `companies`
  ADD CONSTRAINT `peoples-country` FOREIGN KEY (`country_id`) REFERENCES `countries` (`id`) ON DELETE RESTRICT ON UPDATE RESTRICT;

ALTER TABLE `company_people`
  ADD CONSTRAINT `companies-peoples` FOREIGN KEY (`company_id`) REFERENCES `companies` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
  ADD CONSTRAINT `peoples-companies` FOREIGN KEY (`people_id`) REFERENCES `peoples` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,

【问题讨论】：

请分享所有表的架构，尤其是数据透视表，以及您希望获得其他公司的逻辑。

company_people 这对很多人来说都是正确的，为什么您需要单一公司public function company()

我之所以有 company() 也是因为该表最初的结构是这样的，我最近才意识到有些人属于多个公司，否则我将不得不复制人员记录这是不对的。所以 company() 处理主要的公司关系，company() 处理可选的其他公司关系。

【参考方案1】：

您可以使用pluck() 获取所有公司名称然后toArray() 像这样转换成数组

$peoples = People::orderBy($sortField,$sortOrder)
    ->with(['companies','company','country'])
    ->get();

foreach ($peoples as $people) 
    $people->company = '['.$people->company->company.']'; // main company name
    $people->country = '['.$people->country->country.']'; // country name
    $people->otherCompanies = $people->companies->pluck('name')->toArray(); // list of other company names through pivot table

如果你想要otherCompanies 名称作为逗号分隔，那么使用$people->companies->pluck('name')->join(',');

【讨论】：

我认为没有$people->companies 可以做到。 $people->companies() 将创建新查询，并使 with 范围浪费。

@MuhammadDyasYaskur 是的，谢谢