雄辩的关系备忘单

雄辩的关系备忘单

原文：https://medium.com/hackernoon/eloquent-relationships-cheat-sheet-5155498c209

Laravel 雄辩的 ORM 版本 5.5 的备忘单。

一对一的关系

演示详情:

在这个演示中，我们有 2 个模型(车主和汽车，以及 2 个表(车主和汽车)。

业务规则:

车主可以拥有一辆车。 汽车可以归一个车主所有。

关系图:

关系详情:

汽车表应该存储车主T21 的 ID 。

雄辩的模型:

class Owner
{
    public function car()
    {
       return $this->hasOne(Car::class);
    }
}class Car
{
    public function owner()
    {
        return $this->belongsTo(Owner::class);
    }
}

数据库迁移:

Schema::create('owners', function (Blueprint $table) {
    $table->increments('id');
    $table->string('name');
});Schema::create('cars', function (Blueprint $table) {
    $table->increments('id');
    $table->string('name'); $table->integer('owner_id')->unsigned()->index()->nullable();
    $table->foreign('owner_id')->references('id')->on('owners');
});

商店记录:

// Create relation between Owner and Car.$owner->car()->save($car);// Create relation between Car and Owner.$car->owner()->associate($owner)->save();

检索记录:

// Get Owner Car$owner->car;// Get Car Owner$car->owner;

一对多关系

演示详情:

在这个演示中，我们有 2 个模型(小偷和汽车)和 2 个桌子(小偷和汽车)。

业务规则:

这个小偷可以偷很多车。 汽车可以被一个小偷偷走。

关系图:

关系详情:

汽车表应该存储小偷 ID 。

雄辩的模型:

class Thief
{
    public function cars()
    {
       return $this->hasMany(Car::class);
    }
}class Car
{
    public function thief()
    {
        return $this->belongsTo(Thief::class);
    }
}

数据库迁移:

Schema::create('thieves', function (Blueprint $table) {
    $table->increments('id');
    $table->string('name');
});Schema::create('cars', function (Blueprint $table) {
    $table->increments('id');
    $table->string('name'); $table->integer('thief_id')->unsigned()->index()->nullable();
    $table->foreign('thief_id')->references('id')->on('thieves');
});

商店记录:

// Create relation between Thief and Car.$thief->cars()->saveMany([
   $car1, 
   $car2,
]);// Or use the save() function for single model.$thief->cars()->save($car);// Create relation between Car and Thief.$car->thief()->associate($thief)->save();

检索记录:

// Get Thief Car$thief->cars;// Get Car Thief$car->thief;

多态一对多关系

演示详情:

在这个演示中，我们有 3 个模型(男人、女人和汽车)、和 3 张桌子(男人、女人和汽车)。

业务规则:

男(买家)可以买很多车。 女(买家)可以买很多车。 车可以由一个买家(男或女)购买。

关系图:

关系详情:

汽车表应存储买方 ID 和买方类型。 “买手”是对一群模特(男女)的称呼。而且不限于两个。买家类型是模型的真实名称。

雄辩的模型:

class Man
{
    public function cars()
    {
        return $this->morphMany(Car::class, 'buyer');
    }
}class Woman
{
    public function cars()
    {
        return $this->morphMany(Car::class, 'buyer');
    }
}class Car
{
    public function buyer()
    {
        return $this->morphTo();
    }
}

数据库迁移:

Schema::create('men', function (Blueprint $table) {
    $table->increments('id');
    $table->string('name');
});Schema::create('women', function (Blueprint $table) {
    $table->increments('id');
    $table->string('name');
});Schema::create('cars', function (Blueprint $table) {
    $table->increments('id');
    $table->string('name'); $table->integer('buyer_id')->unsigned()->index()->nullable();
    $table->string('buyer_type')->nullable();   
    // or use $table->morphs(‘buyer’); instead of "buyer_id" and "buyer_type"});

商店记录:

// Create relation between buyer (Man/Woman) and Car.$man->cars()->saveMany([
   $car1, 
   $car2,
]);$woman->cars()->saveMany([
   $car1, 
   $car2,
]);// Or use the save() function for single model.$man->cars()->save($car);
$woman->cars()->save($car);// Create relation between Car and buyer (Men/Women).$car1->buyer()->associate($man)->save();
$car2->buyer()->associate($woman)->save();

检索记录:

// Get buyer (Man/Woman) Cars$men->cars
$women->cars// Get Car buyer (Man and Woman)$car->buyer

多对多关系

演示详情:

在这个演示中，我们有 2 个模型( Driver 和 Car)、和 3 个表( drivers 、 cars 和一个名为 car_driver 的数据透视表)。

业务规则:

司机可以开很多车。 车可以由很多司机驾驶。

关系图:

关系详情:

Pivot 表“car_driver”应存储司机 ID 和汽车 ID 。

雄辩的模型:

class Driver
{
    public function cars()
    {
       return $this->belongsToMany(Car::class);
    }
}class Car
{
    public function drivers()
    {
        return $this->belongsToMany(Driver::class);
    }
}

数据库迁移:

Schema::create('drivers', function (Blueprint $table) {
    $table->increments('id');
    $table->string('name');
});Schema::create('cars', function (Blueprint $table) {
    $table->increments('id');
    $table->string('name');
});Schema::create('car_driver', function (Blueprint $table) {
    $table->increments('id'); $table->integer('car_id')->unsigned()->index();
    $table->foreign('car_id')->references('id')->on('cars')->onDelete('cascade'); $table->integer('driver_id')->unsigned()->index();
    $table->foreign('driver_id')->references('id')->on('drivers')->onDelete('cascade');
});

商店记录:

// Create relation between Driver and Car.$driver->cars()->attach([
   $car1->id,
   $car2->id,
]);// Or use the sync() function to prevent duplicated relations.$driver->cars()->sync([
   $car1->id,
   $car2->id,
]);// Create relation between Car and Driver.$car->drivers()->attach([
   $driver1->id,
   $driver2->id,
]);// Or use the sync() function to prevent duplicated relations.$car->drivers()->sync([
   $driver1->id,
   $driver2->id,
]);

检索记录:

// Get Driver Car$driver->cars// Get Car Drivers$car->drivers

多态多对多关系

演示详情:

在这个演示中，我们有 3 个模型(代客、车主和汽车)、和 4 个表(侍者、车主、 汽车和司机)。

业务规则:

代客(司机)可以开多辆车。 车主(司机)可以开多辆车。 车可由多名司机驾驶(代客或/和车主)。

关系图:

关系详情:

枢轴表“司机”应存储司机 ID 、司机 类型和小车 ID 。 “司机”是对一群模特(代客和车主)的称呼。而且不限于两个。驱动类型是模型的真实名称。

雄辩的模型:

class Valet
{
    public function cars()
    {
        return $this->morphToMany(Car::class, 'driver');
    }
}class Owner
{
    public function cars()
    {
        return $this->morphToMany(Car::class, 'driver');
    }
}class Car
{
    public function valets()
    {
        return $this->morphedByMany(Valet::class, 'driver');
    }

    public function owners()
    {
        return $this->morphedByMany(Owner::class, 'driver');
    }
}

数据库迁移:

Schema::create('valets', function (Blueprint $table) {
    $table->increments('id');
    $table->string('name');
});Schema::create('owners', function (Blueprint $table) {
    $table->increments('id');
    $table->string('name');
});Schema::create('drivers', function (Blueprint $table) {
    $table->increments('id'); $table->integer('driver_id')->unsigned()->index();
    $table->string('driver_type');
    // or use $table->morphs(‘driver’); instead of "driver_id" and "driver_type" $table->integer('car_id')->unsigned()->index();
    $table->foreign('car_id')->references('id')->on('cars')->onDelete('cascade');
});

商店记录:

// Create relation between driver (Valet/Owner) and Car.$valet->cars()->saveMany([$car1, $car2]);
$owner->cars()->saveMany([$car1, $car2]);// Or use the save() function for single model.$valet->cars()->save($car1);
$owner->cars()->save($car1);// Create relation between Car and driver (Valet/Owner).$car->valets()->attach([
    $valet1->id,
    $valet2->id,
]);$car->owners()->attach([
    $owner1->id,
    $owner2->id,
]);// Or use the sync() function to prevent duplicated relations.$car->valets()->sync([
    $valet1->id,
    $valet2->id,
]);$car->owners()->sync([
    $owner1->id,
    $owner2->id,
]);

检索记录:

// Get driver (Valet/Owner) Cars$valet->cars
$owner->cars// Get Car drivers (Valet and Owner)$car->owners
$car->valets

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