I am working on a project where am required to implement a database relationship between tables(Trip, Truck, Fuel) . Below is the idea :
A truck has many trips
Each trip has many trucks
Each truck has got a fuel associated with a trip.
Now I was hoping to use Eloquent relationships to solve this but am stuck . How do I get a Fuel transaction and map it to a truck and trip ?
Thanks in advance !
you can use pivot table.
"pivot table is used to build a relationship between two tables where there is a Many to Many relationship."
in your case you can use Many to Many relationship between truck and trip then use fuel like a column in pivot table. it's easier
Eloquent does not support ternary relationships out of the box. This is because typically ternary relationships are incorrectly used when normal binary relationships would be more appropriate. For example I could argue that the Fuel entity is actually metadata on the Truck-Trip relationship and should be placed on the pivot table instead.
If you are completely 100% certain that your ternary relationship is correctly required then I think your best bet is to make a separate model TruckTrip i.e.:
class TruckTrip extends Model {
public function truck() {
return $this->belongsTo(Truck::class);
}
public function trip() {
return $this->belongsTo(Trip::class);
}
public function fuel() {
return $this->belongsTo(Fuel::class);
}
}
Then instead of relating Truck, Trip and Fuel directly you could use: hasManyThrough e.g.
class Trip extends Model {
public function trucks() {
return $this->hasManyThrough(Truck::class, TruckTrip::class);
}
public function fuel() {
return $this->hasManyThrough(Fuel::class, TruckTrip::class);
}
}
Similarly you can relate trucks to trips and fuel requirements and fuel requirements to trucks and trips
Laravel is offering many to many relationship but i prefer if you divided by tow relation.
make a table for this relation have the ID of truck and the ID of trips, then make a relation one to many between truck and this new table and another relation one to many between trip and this new table.
is will be easy for you
Related
I have the following structure:
Charge
id
amount
created_at
..
Payment
id
amount
created_at
..
and a pivot table charge_payment, since one charge can be covered partially by multiple payments.
charge_payment
charge_id
payment_id
amount
The amount column on the pivot table defines the amount that the given Payment covers for the Charge.
And I need to get only the "paid" amount for a Payment.
I have the following models:
// Charge.php
class Charge extends Model
{
public function payments()
{
return $this->belongsToMany('App\Payment')->withPivot('amount');
}
}
// Payment.php
class Payment extends Model
{
public function charges()
{
return $this->belongsToMany('App\Charge')->withPivot('amount');
}
}
I want to be able to get only the paid amount with:
$payment = Payment::find(..);
$paid_amount = $payment->charges->sum('pivot.amount');
However, with this approach the related models are loaded from the database and I won't be needing them.
Is there a way to load only the additional pivot column without the related models?
Thank you very much!
Firstly, if one Payment can be always related only to one Charge, I would advise you to change the relationship from many-to-many to one-to-many (it will be just more correct and simpler).
Than you can simple use aggregate function (in your case withSum) which will return you only resulting values without relationship Models.
$payment = Payment::withSum('payments', 'amount')->find(..);
{{ $payment->payments_sum_amount }}
In a project, let's say that we have Customers, and each customer can have one Voucher. The voucher, though, may be for a different thing for different customers - maybe for a Hote, a Car or a Flight.
We have a table of flight voucher codes, a table of hotel voucher codes and a table of car voucher codes.
When a customer is allocated a voucher, therefore, we allocated them the next code for the relevant thing that they're getting a voucher for. But rather than have multiple tables (customer_car_voucher, customer_hotel_voucher, and so on) I would rather have a Voucher table which is, in turn, linked to the relevant voucher type.
What I want to be able to do is just go $customer->voucher->code to get the relevant code, whether that be a flight, a hotel or a car. Other vouchers may be added at a later date, you see, for different things.
I think I can do this using morphable relationships - the voucher morphsTo car, hotel and flight, so within the the voucher table there is a "voucherable_type" and a "voucherable_id". But damned if I can get it to work.
Any help, please? Am I going about it wrong?
you arte right. and for a hint use:
public function customer()
{
return $this->belongsTo(Customer::class):
}
public function voucherable()
{
return $this->morphTo();
}
in voucher model.
and for each flight,car,hotel include:
public function voucher(){
return $this->morphOne(Voucher::class,'voucherable');
}
you can see Laravel morph relationship too for more help.
In Laravel's Eloquent ORM is used for morphable relationships.
First, create two Models AirVoucher and Voucher.
First, the AirVoucher model uses the following relationship.
public function voucher()
{
return $this->morphOne(Voucher::class, 'voucherable');
}
Second, the Voucher model uses the following relationship.
public function voucherable()
{
return $this->morphTo();
}
You can use the following Laravel official relationship document for more help.
Laravel Morph Relationships.
you must use laravel Polymorphic Relationships.
in Voucher model set this model as polymorph model(function name = modelname+"able"):
public function voucherable() \Illuminate\Database\Eloquent\Relations\MorphTo
{
return $this->morphTo();
}
then in Car model (or hotel/fight) set realation(function name= polymorph name):
if each car has one voucher, use morphOne:
public function files(): \Illuminate\Database\Eloquent\Relations\MorphOne
{
return $this->morphOne(Voucher::class, 'voucherable');
}
if each car has many voucher, use morphMany:
public function files(): \Illuminate\Database\Eloquent\Relations\MorphMany
{
return $this->morphMany(Voucher::class, 'voucherable');
}
Retrieving The Relationship
$car = Car::find(1);
$vocher = $car->voucher;
laravel docs
In Laravel, is it possible to put a relationship within a relationship?
Basically, I already have a relationship set up, but I then need another relationship for that relationship (if that makes sense).
My two models:
Store
Supplier
My relationship model for Store and Supplier:
SupplierStore
store_id
supplier_id
As you can see, I have many stores and suppliers, each of whom can relate to each other through the SupplierStore table.
This works perfectly.
My problem is that for each relationship (of Store and Supplier) there can be
many Delivery Days.
My HasMany relationship:
DeliveryDay
supplier_store_id
day
I thought if I go into the SupplierStore model and add:
public function days()
{
return $this->hasMany('App\DeliveryDay');
}
Would work, but there is no way I can seem to access this data through eloquent?
I was hoping to do something like this:
$supplier = Supplier::find($id);
$supplier->store->pivot->days
The pivot (SupplierStore) would hold the relationship of that specific relation and I could grab the days.
Can anyone help me figure out what I need to do to achieve this? Your time is much appreciated. After googling for hours, my head hurts so much. :)
You could access each day like this:
public function getDays($id)
{
$supplier = Supllier::find($id);
foreach($supplier->stores() as $store)
{
foreach($store->days() as $day)
{
echo $day->day;
}
}
}
Or get all days
$supplier->stores->days;
I've one many to many relationship between Entities and Affiliated Tables,
basically an affiliated can attend to many entities(example, medical services, dentist offices). One Entity can be visited by one or many affiliated.
Additionaly , one or more benefits can be occupied by one affiliated in a particular entity. As shown in the image.
I want to be able to answer queries like, which benefits where used by the affiliated in a particular entity.
Should i create a new Model, how should i rewrite the many-to-many relationship for ORM.
Thanks in advance!
Don't need a Affiliated_has_Entities model.
You could write the relationships as below, remember to check for arguments and its order in the belognsToMany relationship (sorry for misspelled words)
Entities model
public function afilliateds(){
return $this->belongsToMany('Afilliated', 'Afilliated_has_Entities');
}
Afilliated model
public function entities(){
return $this->belongsToMany('Entities', 'Afilliated_has_Entities');
}
public function benefits(){
return $this->belongsToMany('Entities', 'Afilliated_has_Entities');
}
Benefits model
public function entites(){
return $this->belongsToMany('Entities', 'Afilliated_has_Entities');
}
And so on..
I hope it helps
I have a two Models: a Deal is started on one system by customers, and a Sale is started on another system by a salesman. I have an intermediate table dms_matches that forms a many-to-many relationship between those models, and includes a confidence score.
Customers can start many deals, the confidence score measures how likely the customer Deal is the exact one that initiated the final Sale transaction. (e.g., one system says first name is "Joe" and the other says "Joseph", or customer got upsold so Sale contains a related but different product than Deal)
I have a working many-to-many relationship on Sale to return all matched Deals:
public function deals()
{
return $this->belongsToMany('App\Models\Deal', 'dms_matches', 'dms_sale_id')
->orderBy('dms_matches.confidence', 'DESC')
->withPivot('confidence');
}
Now I would like a relationship that returns the exactly one Deal with the highest confidence score. (I want a relationship so I can get eager loading and caching.)
This works, but returns a collection of length one:
public function best_deal()
{
return $this->deals()->limit(1);
}
This works, but isn't a relationship, so it doesn't work with eager loading.
public function getBestDealAttribute()
{
return $this->deals()->first();
}
How can I build something that behaves like a hasOne or belongsTo relationship, but uses an intermediate table?