这篇文章将为大家详细讲解有关Laravel之模型关联预加载的示例分析，小编觉得挺实用的，因此分享给大家做个参考，希望大家阅读完这篇文章后可以有所收获。
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Laravel学习笔记之模型关联预加载
说明：本文主要说明Laravel Eloquent的延迟预加载(Eager Loading)，使用延迟预加载来减少MySQL查询次数。同时，作者会将开发过程中的一些截图和代码黏上去，提高阅读效率。
备注：现在有4张表：商家表merchants、商家电话表phones、商家拥有的店铺shops表和店铺里的商品表products。并且关系是：
[
'merchants_phones' => 'one-to-one',
'merchants_shops' => 'one-to-many',
'shops_products' => 'one-to-many',
]
现在要求做出一个页面以列表形式显示每个店铺，每个店铺块包含店铺信息如标题、包含店铺商家信息如姓名和电话、包含拥有的商品信息如介绍和价格。看看有没有预加载会有什么不同。
开发环境：Laravel5.1+MAMP+PHP7+MySQL5.5
先写个店铺列表页
1.先装上开发插件三件套(具体可参考：Laravel学习笔记之Seeder填充数据小技巧)
不管咋样，先装上开发插件三件套：
composer require barryvdh/laravel-debugbar --dev
composer require barryvdh/laravel-ide-helper --dev
composer require mpociot/laravel-test-factory-helper --dev
//config/app.php
/**
*Develop Plugin
*/
Barryvdh\Debugbar\ServiceProvider::class,
Mpociot\LaravelTestFactoryHelper\TestFactoryHelperServiceProvider::class,
Barryvdh\LaravelIdeHelper\IdeHelperServiceProvider::class,
2.写上表字段、表关联和测试数据填充器Seeder
依次输入指令：
php artisan make:model Merchant -m
php artisan make:model Phone -m
php artisan make:model Shop -m
php artisan make:model Product -m
写上表字段和表关联：
class CreateMerchantsTable extends Migration
{
/**
* Run the migrations.
*
* @return void
*/
public function up()
{
Schema::create('merchants', function (Blueprint $table) {
$table->increments('id');
$table->string('username')->unique();
$table->string('email')->unique();
$table->string('first_name');
$table->string('last_name');
$table->timestamps();
});
}
/**
* Reverse the migrations.
*
* @return void
*/
public function down()
{
Schema::drop('merchants');
}
}
class CreatePhonesTable extends Migration
{
/**
* Run the migrations.
*
* @return void
*/
public function up()
{
Schema::create('phones', function (Blueprint $table) {
$table->increments('id');
$table->integer('number')->unsigned();
$table->integer('merchant_id')->unsigned();
$table->timestamps();
$table->foreign('merchant_id')
->references('id')
->on('merchants')
->onUpdate('cascade')
->onDelete('cascade');
});
}
/**
* Reverse the migrations.
*
* @return void
*/
public function down()
{
Schema::table('phones', function($table){
$table->dropForeign('merchant_id'); // Drop foreign key 'user_id' from 'posts' table
});
Schema::drop('phones');
}
}
class CreateShopsTable extends Migration
{
/**
* Run the migrations.
*
* @return void
*/
public function up()
{
Schema::create('shops', function (Blueprint $table) {
$table->increments('id');
$table->string('name');
$table->string('slug')->unique();
$table->string('site');
$table->integer('merchant_id')->unsigned();
$table->timestamps();
$table->foreign('merchant_id')
->references('id')
->on('merchants')
->onUpdate('cascade')
->onDelete('cascade');
});
}
/**
* Reverse the migrations.
*
* @return void
*/
public function down()
{
Schema::table('shops', function($table){
$table->dropForeign('merchant_id'); // Drop foreign key 'user_id' from 'posts' table
});
Schema::drop('shops');
}
}
class CreateProductsTable extends Migration
{
/**
* Run the migrations.
*
* @return void
*/
public function up()
{
Schema::create('products', function (Blueprint $table) {
$table->increments('id');
$table->string('name');
$table->text('short_desc');
$table->text('long_desc');
$table->double('price');
$table->integer('shop_id')->unsigned();
$table->timestamps();
$table->foreign('shop_id')
->references('id')
->on('shops')
->onUpdate('cascade')
->onDelete('cascade');
});
}
/**
* Reverse the migrations.
*
* @return void
*/
public function down()
{
Schema::table('products', function($table){
$table->dropForeign('shop_id'); // Drop foreign key 'user_id' from 'posts' table
});
Schema::drop('products');
}
}
/**
* App\Merchant
*
* @property integer $id
* @property string $username
* @property string $email
* @property string $first_name
* @property string $last_name
* @property \Carbon\Carbon $created_at
* @property \Carbon\Carbon $updated_at
* @property-read \App\Phone $phone
* @property-read \Illuminate\Database\Eloquent\Collection|\App\Shop[] $shops
* @method static \Illuminate\Database\Query\Builder|\App\Merchant whereId($value)
* @method static \Illuminate\Database\Query\Builder|\App\Merchant whereUsername($value)
* @method static \Illuminate\Database\Query\Builder|\App\Merchant whereEmail($value)
* @method static \Illuminate\Database\Query\Builder|\App\Merchant whereFirstName($value)
* @method static \Illuminate\Database\Query\Builder|\App\Merchant whereLastName($value)
* @method static \Illuminate\Database\Query\Builder|\App\Merchant whereCreatedAt($value)
* @method static \Illuminate\Database\Query\Builder|\App\Merchant whereUpdatedAt($value)
* @mixin \Eloquent
*/
class Merchant extends Model
{
/**
* @return \Illuminate\Database\Eloquent\Relations\HasOne
*/
public function phone()
{
return $this->hasOne(Phone::class, 'merchant_id');
}
/**
* @return \Illuminate\Database\Eloquent\Relations\HasMany
*/
public function shops()
{
return $this->hasMany(Shop::class, 'merchant_id');
}
}
/**
* App\Phone
*
* @property integer $id
* @property integer $number
* @property integer $merchant_id
* @property \Carbon\Carbon $created_at
* @property \Carbon\Carbon $updated_at
* @property-read \App\Merchant $merchant
* @method static \Illuminate\Database\Query\Builder|\App\Phone whereId($value)
* @method static \Illuminate\Database\Query\Builder|\App\Phone whereNumber($value)
* @method static \Illuminate\Database\Query\Builder|\App\Phone whereMerchantId($value)
* @method static \Illuminate\Database\Query\Builder|\App\Phone whereCreatedAt($value)
* @method static \Illuminate\Database\Query\Builder|\App\Phone whereUpdatedAt($value)
* @mixin \Eloquent
*/
class Phone extends Model
{
/**
* @return \Illuminate\Database\Eloquent\Relations\BelongsTo
*/
public function merchant()
{
return $this->belongsTo(Merchant::class, 'merchant_id');
}
}
/**
* App\Product
*
* @property integer $id
* @property string $name
* @property string $short_desc
* @property string $long_desc
* @property float $price
* @property integer $shop_id
* @property \Carbon\Carbon $created_at
* @property \Carbon\Carbon $updated_at
* @property-read \Illuminate\Database\Eloquent\Collection|\App\Shop[] $shop
* @method static \Illuminate\Database\Query\Builder|\App\Product whereId($value)
* @method static \Illuminate\Database\Query\Builder|\App\Product whereName($value)
* @method static \Illuminate\Database\Query\Builder|\App\Product whereShortDesc($value)
* @method static \Illuminate\Database\Query\Builder|\App\Product whereLongDesc($value)
* @method static \Illuminate\Database\Query\Builder|\App\Product wherePrice($value)
* @method static \Illuminate\Database\Query\Builder|\App\Product whereShopId($value)
* @method static \Illuminate\Database\Query\Builder|\App\Product whereCreatedAt($value)
* @method static \Illuminate\Database\Query\Builder|\App\Product whereUpdatedAt($value)
* @mixin \Eloquent
*/
class Product extends Model
{
/**
* @return \Illuminate\Database\Eloquent\Relations\BelongsTo
*/
public function shop()
{
return $this->belongsTo(Shop::class, 'shop_id');
}
}
/**
* App\Shop
*
* @property integer $id
* @property string $name
* @property string $slug
* @property string $site
* @property integer $merchant_id
* @property \Carbon\Carbon $created_at
* @property \Carbon\Carbon $updated_at
* @property-read \Illuminate\Database\Eloquent\Collection|\App\Merchant[] $merchant
* @property-read \Illuminate\Database\Eloquent\Collection|\App\Product[] $products
* @method static \Illuminate\Database\Query\Builder|\App\Shop whereId($value)
* @method static \Illuminate\Database\Query\Builder|\App\Shop whereName($value)
* @method static \Illuminate\Database\Query\Builder|\App\Shop whereSlug($value)
* @method static \Illuminate\Database\Query\Builder|\App\Shop whereSite($value)
* @method static \Illuminate\Database\Query\Builder|\App\Shop whereMerchantId($value)
* @method static \Illuminate\Database\Query\Builder|\App\Shop whereCreatedAt($value)
* @method static \Illuminate\Database\Query\Builder|\App\Shop whereUpdatedAt($value)
* @mixin \Eloquent
*/
class Shop extends Model
{
/**
* @return \Illuminate\Database\Eloquent\Relations\BelongsTo
*/
public function merchant()
{
return $this->belongsTo(Merchant::class, 'merchant_id');
}
/**
* @return \Illuminate\Database\Eloquent\Relations\HasMany
*/
public function products()
{
return $this->hasMany(Product::class, 'shop_id');
}
}别忘了利用下开发三件套输入指令：
php artisan ide-helper:generate
php artisan ide-helper:models
php artisan test-factory-helper:generate
表的关系如图：
然后写Seeder，可以参考Laravel学习笔记之Seeder填充数据小技巧:
php artisan make:seeder MerchantTableSeeder
php artisan make:seeder PhoneTableSeeder
php artisan make:seeder ShopTableSeeder
php artisan make:seeder ProductTableSeeder
class MerchantTableSeeder extends Seeder
{
/**
* Run the database seeds.
*
* @return void
*/
public function run()
{
$faker = Faker\Factory::create();
$datas = [];
foreach (range(1, 20) as $key => $value) {
$datas[] = [
'username' => $faker->userName ,
'email' => $faker->safeEmail ,
'first_name' => $faker->firstName ,
'last_name' => $faker->lastName ,
'created_at' => \Carbon\Carbon::now()->toDateTimeString(),
'updated_at' => \Carbon\Carbon::now()->toDateTimeString()
];
}
DB::table('merchants')->insert($datas);
}
}
class PhoneTableSeeder extends Seeder
{
/**
* Run the database seeds.
*
* @return void
*/
public function run()
{
$faker = Faker\Factory::create();
$merchant_ids = \App\Merchant::lists('id')->toArray();
$datas = [];
foreach (range(1, 20) as $key => $value) {
$datas[] = [
'number' => $faker->randomNumber() ,
'merchant_id' => $faker->randomElement($merchant_ids) ,
'created_at' => \Carbon\Carbon::now()->toDateTimeString(),
'updated_at' => \Carbon\Carbon::now()->toDateTimeString()
];
}
DB::table('phones')->insert($datas);
}
}
class ShopTableSeeder extends Seeder
{
/**
* Run the database seeds.
*
* @return void
*/
public function run()
{
$faker = Faker\Factory::create();
$merchant_ids = \App\Merchant::lists('id')->toArray();
$datas = [];
foreach (range(1, 40) as $key => $value) {
$datas[] = [
'name' => $faker->name ,
'slug' => $faker->slug ,
'site' => $faker->word ,
'merchant_id' => $faker->randomElement($merchant_ids) ,
'created_at' => \Carbon\Carbon::now()->toDateTimeString(),
'updated_at' => \Carbon\Carbon::now()->toDateTimeString()
];
}
DB::table('shops')->insert($datas);
}
}
class ProductTableSeeder extends Seeder
{
/**
* Run the database seeds.
*
* @return void
*/
public function run()
{
$faker = Faker\Factory::create();
$shop_ids = \App\Shop::lists('id')->toArray();
$datas = [];
foreach (range(1, 30) as $key => $value) {
$datas[] = [
'name' => $faker->name ,
'short_desc' => $faker->text ,
'long_desc' => $faker->text ,
'price' => $faker->randomFloat() ,
'shop_id' => $faker->randomElement($shop_ids) ,
'created_at' => \Carbon\Carbon::now()->toDateTimeString() ,
'updated_at' => \Carbon\Carbon::now()->toDateTimeString()
];
}
DB::table('products')->insert($datas);
}
}
php artisan db:seed3.写个简单View视图
(1)用Repository Pattern来组织代码
//app/Repository
namespace App\Repository;
interface ShopRepositoryInterface
{
public function all();
}
//app/Repository/Eloquent
namespace App\Repository\Eloquent;
use App\Repository\ShopRepositoryInterface;
use App\Shop;
class ShopRepository implements ShopRepositoryInterface
{
/**
* @var Shop
*/
public $shop;
public function __construct(Shop $shop)
{
$this->shop = $shop;
}
public function all()
{
// TODO: Implement all() method.
$shops = $this->shop->all();
return $shops;
}
}
//app/provider/ShopRepositoryServiceProvider
//php artisan make:provider ShopRepositoryServiceProvider
/**
* Register the application services.
*
* @return void
*/
public function register()
{
$this->app->bind(ShopRepositoryInterface::class, ShopRepository::class);
}
//app/Http/Controllers/ShopController.php
class ShopController extends Controller
{
/**
* @var ShopRepositoryInterface
*/
public $shop;
/**
* ShopController constructor.
* @param ShopRepositoryInterface $shopRepositoryInterface
*/
public function __construct(ShopRepositoryInterface $shopRepositoryInterface)
{
$this->shop = $shopRepositoryInterface;
}
public function all()
{
$shops = $this->shop->all();
return view('shop.index', compact('shops'));
}
}
//视图
//resources/views/shop/layout.blade.php
Bootstrap Template
@yield('content')
