Now I have those business logic, but don't know how to define it in Laravel.
First, there are two basic model named contact and project, and contact and project model owns many-to-many relations so I defined them like below:
class Contact extends Model{
public function projects(){
return $this->belongsToMany('App\Project', 'proj_staff')
->withPivot('role', 'superior');
}
}
And the same as Project:
class Project extends Model{
public function contacts(){
return $this->belongsToMany('App\Contact', 'proj_staff')
->withPivot('role', 'superior');
}
}
As you see, every contact has a superior in his project or not, so the question comes with it that how can I define a relation to get access to superior like this: $contact->projects[0]->superiors, and the superiors has better return a Model Collection rather than just id.
Thx any way.
You are accessing projects from your contacts & you want to access projects & contacts pivot table proj_staff info from your projects model.
So you have to create another relation in your in your Project
model to access the data from your pivot table
class Project extends Model{
public function contacts(){
return $this->belongsToMany('App\Contact', 'proj_staff')
->withPivot('role', 'superior');
}
//your project table has one to many many relationship with proj_staff table
public function superiors(){
return $this->hasMany('App\ProjStaff', 'superior', 'superior');//set relation keys I assume it's superior is local and foreign key
}
}
//Create ProjStaff Pivot Table Model under app directory same level with your Contact model
class ProjStaff extends Model{
//add fillable
//add table name
}
Now you can easily access superior like $contact->projects[0]->superiors->pluck('superior')->all()
Related
A contract has a representative (which is a user).
Currently I get this relationship with an belongsTo directly like this in my Contract model:
class Contract extends Model
{
public function representative()
{
return $this->belongsTo(User::class);
}
I would like to be able to retrieve this relationship through the organization_user table and retrieve the "position" attribute.
I think I should use the hasOneThrough relationship but I can't get what I'm looking for.
class Contract extends Model
{
public function representative()
{
return $this->hasOneThrough(User::class, OrganizationUser::class);
}
Not sure if you're in a position to change your DB structure, but it seems to me that your table contracts and organization_user are duplicating each other, storing the same data.
Would it make sense to leave only one table organization_user as a pivot table with the position?
Then you wouldn't need to make the big loop over few relationship to get the needed data.
I would like to observe a pivot table in which, rows are created with an attach method in a specific model, is there a way to Observe that pivot table through the attach method that is responsible for creating rows?
after struggling some time, I came to answer my question,
so in order to observe a table whose rows are created by the attach method, we will need to do 3 things
1- we will need to create a model that extends
$Illuminate\Database\Eloquent\Relations\Pivot
2- Connect the model to the database table with this line:
protected $table = 'data_base_table_name';
3- use the method 'using' at the end of the BelongsToMany relationship in each model that is related to the pivot table
Example:
let's say we have a model called Student and another one called Group, we have also a pivot table called group_students that is filled with the attach method since we have a student BelongsToMany groups and Group BelongsToMany Students,
we will need to create a model named GroupStudent that extends
Illuminate\Database\Eloquent\Relations\Pivot
and link it to the group_students by adding the following line in the GroupStudent Class:
protected $table = 'group_student'
After that, we will need to add the using method The BelongsToMany relations in the Student Model and the Group Model like the following:
public function students()
{
return $this->BelongsToMany(Student::class)->using(GroupStudent::class);
}
and
public function groups()
{
return $this->belongsToMany(Group::class)->using(GroupStudent::class);
}
And here we go, now whenever I create a row in the group_students table through the attach method, this will be observed and the method created will be executed.
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
Is there a simple solution to detach (without deleting) all related models through a hasMany Relation on a model?
For example, I have two tables:
College (id, name)
Student (id, name, college_id(nullable) )
In the College model I define this relationship:
class College extends Model
{
public function students()
{
return $this->hasMany('App\Student','college_id','id');
}
}
What is the best way to detach all current College students from the College (i.e, get all the students of the college and set their college_id to null)?
Is there an easy way to detach all students from the College model using eloquent?
Something like
class College extends Model
{
...
public function detachAllStudents()
{
...
}
}
P.S. already have read this question Laravel hasMany detach, but get errors when I try to apply it to my application
Yes, you can detach all the college students as below. Actually, we already have the college_id in your students table and we have to make this college_id null somehow. This is not called detach in Eloquent. The word detach come when you have many to many relationships. So, let's just update the students and see if it works or not.
$college->students()->update(['college_id' => null);
So, you method can be completed as below:
public function detachAllStudents()
{
$college->students()->update(['college_id' => null]);
}
That's it!
Directly from the documentation https://laravel.com/docs/5.8/eloquent-relationships:
Toggling Associations
The many-to-many relationship also provides a toggle method which "toggles" the attachment status of the given IDs. If the given ID is currently attached, it will be detached. Likewise, if it is currently detached, it will be attached:
$user->roles()->toggle([1, 2, 3]);
Despite Imran answer perfectly fits this scenario I would add a more generic approach. Let's say $college respects an interface instead of an implementation, you wouldn't know the foreign key at run time.
<?php
use Illuminate\Database\Eloquent\Relations\HasMany;
interface HasStudents {
public function students(): HasMany;
}
class College extends Model implements HasStudents
{
public function students(): HasMany;
{
return $this->hasMany(Student::class, 'college_id', 'id');
}
}
function detachStudents(HasStudents $model): void {
$studentsRelationship = $model->students();
$studentsRelationship->update([
$studentsRelationship->getQualifiedForeignKeyName() => null
]);
}
detachStudents($college);
Using Laravel, I have the following code
$review = Review::find(1);
$review->delete();
Review has a many to many relationship defined with a Product entity. When I delete a review, I'd expect it to be detached from the associated products in the pivot table, but this isn't the case. When I run the code above, I still see the linking row in the pivot table.
Have I missed something out here or is this the way Laravel works? I'm aware of the detach() method, but I thought that deleting an entity would also detach it from any related entities automatically.
Review is defined like this:
<?php
class Review extends Eloquent
{
public function products()
{
return $this->belongsToMany('Product');
}
}
Product is defined like this:
<?php
class Product extends Eloquent
{
public function reviews()
{
return $this->belongsToMany('Review');
}
}
Thanks in advance.
The detach method is used to release a relationship from the pivot table, whilst delete will delete the model record itself i.e. the record in the reviews table. My understanding is that delete won't trigger the detach implicitly. You can use model events to trigger a cleanup of the pivot table, though, using something like:
protected static function booted()
{
static::deleting(function ($review) {
$review->product()->detach()
});
}
Also, I would suggest that the relationship would be a one to many, as one product would have many reviews, but one review wouldn't belong to many products (usually).
class Review extends \Eloquent {
public function product()
{
return $this->belongsTo('Product');
}
}
class Product extends \Eloquent {
public function reviews()
{
return $this->hasMany('Review');
}
}
Of course, this would then require that you tweak your database structure. If you wanted to leave the database structure and your current relationships as they are, the other option would be to apply a foreign key constraint on the pivot table, such that when either a review or product is removed, you could cascade the delete on the pivot table.
// Part of a database migration
$table->foreign('product_id')->references('id')->on('products')->onDelete('cascade');
$table->foreign('review_id')->references('id')->on('reviews')->onDelete('cascade');
Edit: In adding the constraint, you push the cleanup work onto the database, and don't have to worry about handling it in code.
Simpler Steps:
In this example an Account has many Tags:
To delete the Tags, then the Account do this:
// delete the relationships with Tags (Pivot table) first.
$account->find($this->accountId)->tags()->detach();
// delete the record from the account table.
$account->delete($this->accountId);
On the Pivot Table make sure you have ->onDelete('cascade');
$table->integer('account_id')->unsigned()->index();
$table->foreign('account_id')->references('id')->on('accounts')->onDelete('cascade');
$table->integer('tag_id')->unsigned()->index();
$table->foreign('tag_id')->references('id')->on('tags')->onDelete('cascade');
$review->product()->sync([]) also works.
However $review->product()->detach() is much more explicit.
public function destroy($id)
{
$review = Review::find($id);
$review ->tagged_users()->detach();
return $review ->delete();
}
also works
If that way doesn't solve your problem, you can delete Pivot table records to using the DB option like below ;
DB::table('any_pivot_table')->where('x_column', $xParameter)->delete();
You can solve the problem just like this.
Enjoy your coding !
i guess you have a error in your models relationship conception, the product has many reviews but the review associated with one product so you have here one to many relationship.
but in general the answer in the general case will be using:
$product->reviews()->sync([]);