Overview
Source: https://medium.com/@Mahmoud_Zalt/eloquent-relationships-cheat-sheet-5155498c209
| One to one ( 1-1) |
One to many ( 1-n) |
Poly one to many ( 1x-n) |
Many to many ( n-n) |
Poly many to many ( nx-n) |
|
|---|---|---|---|---|---|
| Number of models | 2 only | 2 only | 3 and above | 2 only | 3 and above |
| Number of tables | 2 (1/model) | 2 (1/model) | 3+ (1/model) | 3 (1/model + pivot) | 4+ (1/model + pivot) |
| Pivot table | - | - | - | required | required |
| Model A relation | hasOne |
hasMany |
morhpMany (all) |
belongsToMany |
morphToMany (all) |
| Model B relation | belongsTo |
belongsTo |
morphTo |
belongsToMany |
morphToMany |
| Set relation on Model A | save(B) |
saveMany([B1, B2])save(B) |
saveMany([B1, B2])save(B) |
attach([B1, B2])sync([B1, B2]) |
saveMany([B1, B2])save(B) |
| Set relation on Model B | associate(A)->save() |
associate(A)->save() |
associate(A)->save() |
attach([A1, A2])sync([A1, A2]) |
attach([A1, A2])sync([A1, A2]) |
| Foreign key holder | Model B table (A_id) |
Model B table (A_id) |
Model B table (A_id, A_type) |
Pivot table (A_id, B_id) |
Pivot table (A_id, A_type, B_id) |
One to One Relationship
Demo details:
In this demo we have 2 models (Owner and Car), and 2 tables (owners and cars).
Business Rules:
The Owner can own one Car. The Car can be owned by one Owner.
Relations Diagram:
Relationship Details:
The Cars table should store the Owner ID.
Eloquent Models:
class Owner
{
public function car()
{
return $this->hasOne(Car::class);
}
}
class Car
{
public function owner()
{
return $this->belongsTo(Owner::class);
}
}Database Migrations:
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');
});Store Records:
// Create relation between Owner and Car.
$owner->car()->save($car);
// Create relation between Car and Owner.
$car->owner()->associate($owner)->save();Retrieve Records:
// Get Owner Car
$owner->car;
// Get Car Owner
$car->owner;One to Many Relationship
Demo details:
In this demo we have 2 models (Thief and Car), and 2 tables (thieves and cars).
Business Rules:
The Thief can steal many Cars. The Car can be stolen by one Thief.
Relations Diagram:
Relationship Details:
The Cars table should store the Thief ID.
Eloquent Models:
class Thief
{
public function cars()
{
return $this->hasMany(Car::class);
}
}
class Car
{
public function thief()
{
return $this->belongsTo(Thief::class);
}
}Database Migrations:
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');
});Store Records:
// 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();Retrieve Records:
// Get Thief Car
$thief->cars;
// Get Car Thief
$car->thief;Polymorphic One to Many Relationship
Demo details:
In this demo we have 3 models (Man, Woman and Car), and 3 tables (men, women and cars).
Business Rules:
The Man (buyer) can buy many Cars. The Woman (buyer) can buy many Cars. The Car can be bought by one buyer (Man or Woman).
Relations Diagram:
Relationship Details:
The Car table should store the Buyer ID and the Buyer Type. “buyer” is a name given to a group of models (Man and Woman). And it’s not limited to two. The buyer type is the real name of the model.
Eloquent Models:
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();
}
}Database Migrations:
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();
});Store Records:
// 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();Retrieve Records:
// Get buyer (Man/Woman) Cars
$men->cars
$women->cars
// Get Car buyer (Man and Woman)
$car->buyerMany to Many Relationship
Demo details:
In this demo we have 2 models (Driver and Car), and 3 tables (drivers, cars and a pivot table named car_driver).
Business Rules:
The Driver can drive many Cars. The Car can be driven by many Drivers.
Relations Diagram:
Relationship Details:
The Pivot table “car_driver” should store the Driver ID and the Car ID.
Eloquent Models:
class Driver
{
public function cars()
{
return $this->belongsToMany(Car::class);
}
}
class Car
{
public function drivers()
{
return $this->belongsToMany(Driver::class);
}
}Database Migrations:
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');
});Store Records:
// 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,
]);Retrieve Records:
// Get Driver Car
$driver->cars
// Get Car Drivers
$car->driversPolymorphic Many to Many Relationship
Demo details:
In this demo we have 3 models (Valet, Owner and Car), and 4 tables (valets, owners, cars and drivers).
Business Rules:
The Valet (driver) can drive many Cars. The Owner (driver) can drive many Cars. The Car can be driven by many drivers (Valet or/and Owner).
Relations Diagram:
Relationship Details:
The Pivot table “drivers” should store the Driver ID, Driver Type and the Car ID. “driver” is a name given to a group of models (Valet and Owner). And it’s not limited to two. The driver type is the real name of the model.
Eloquent Models:
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(Man::class, 'driver');
}
public function owners()
{
return $this->morphedByMany(Woman::class, 'driver');
}
}Database Migrations:
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');
$table->integer('car_id')->unsigned()->index();
$table->foreign('car_id')->references('id')->on('cars')->onDelete('cascade');
});Store Records:
// 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,
]);Retrieve Records:
// Get driver (Valet/Owner) Cars
$valet->cars
$owner->cars
// Get Car drivers (Valet and Owner)
$car->owners
$car->valets