Laravel Eager Loading, multiple same hasOne relations - php

I have 2 simple models. First, one is called Builds and the second one is called SlotOptions. Each build can have like 5 assigned slots.
class BuildDB extends Model
And has 5 such relations slot1-5 and id changes to slot1-5_id
public function slot1()
{
return $this->hasOne('\App\SlotOptions', 'id', 'slot1_id');
}
In the controller I call it such way;
BuildDB::with([ 'slot1', 'slot2', 'slot3', 'slot4', 'slot5'])->find(5);
\App\SlotOptions model doesn't contain any extra coding.
This generates 5 "same" queries. - atm the eager loading would work if I get a list of builds and each slot would have whereIn clause, is it possible to have it a one big wherein the clause, or does it require to change the DB schema.

It's not possible to optimize eager loading in this case.
I recommend that you change your database schema to a many-to-many relationship.
This design is more flexible, it allows you to easily add more slots in the future.
Create a pivot table named build_slot_option with these columns: build_id, slot_option_id
Add an additional column if you want to number/order the slots.
Then define a BelongsToMany relationship:
class BuildDB extends Model
{
public function slots()
{
return $this->belongsToMany(
SlotOptions::class, 'build_slot_option', 'build_id', 'slot_option_id'
);
}
}
BuildDB::with('slots')->find(5);

Related

I don’t know how to get data in laravel correctly by linking the data in this database

In this figure, the remaining tables are linked to the datainfo table. I need to retrieve the entire table data from the datainfo table.
In this picture I have shown the tables themselves
You can create Eloquent Models for each table and define Relationships among them. This is the Correct Laravel Way.
Let's assume Your datainfo table represents your Datainfo model,
Your cars table represents Car model. Same as washtypes and boxes.
then depending on your relation type defined the relation in Datainfo model.
class Datainfo extends Model
{
public function cars()
{
return $this->hasMany(Car::class);
}
}
You also can use hasOne instead of hasMany for one - to one relation
Similarly, create relation defining functions as washtypes() and boxes().
Then To get Datainfo with all related data using something like think in your controller
return Datainfo::with('cars','washtypes','boxes')->get();
Alternatively, you can get the count
return Datainfo::with('cars','washtypes','boxes')->count();
To get a count on a date
return Datainfo::with('cars','washtypes','boxes')->where('created_at',$date_var)->count();
If you only want Datainfo that has relation with cars, washtypes or boxes:
return Datainfo::has('cars','washtypes','boxes')->where('created_at',$date_var)->count();
Use laravel eloquent join clauses, https://laravel.com/docs/8.x/queries#joins
For total amount in same day
You can use eloquent sum and group by methods based on the date

Laravel model relation - change to mutator, without chaning anything in cotrollers

I have 2 tables, estimates and models.
There's a 1-to-1 relation between the two.
I want to move model names from the models table to the estimates table. That will be done with a script that I will have to write myself.
The way this database was set up was wrong, for many reasons I don't need to specify here.
The models table has only 2 columns - id and name.
I access this relation in a lot of controllers, and views all over my app :
$estimate->model_info->name
So I would keep both the models table (with no records) and the Model.php model, keep the old code in the controllers and views, but the new code of accessing model names would be just :
$estimate->name
In the Estimate.php model I have this relation :
public function model_info() {
return $this->hasOne('App\Models\Model', 'id', 'model_id');
}
How can I just change this relation into a mutator, so the old way of accessing model names and the new way would work at the same time?
I've tried the withDefault() callback method with no luck, it returns an empty value :
public function model_info() {
return $this->hasOne('App\Models\Model', 'id', 'model_id')
->withDefault([
'name' => $this->attribute->name
]);
}
Do I have to update my code in all controllers and views or if there's an easier way to do this?

Laravel relationship eager loading limiting all results instead of model specific

I have a nested relationship like:
Model One has many Model Twos which has many Model Threes.
The aim is to get all Model Ones and all their Model Twos and for the each of the Model Twos only get the latest Model Three.
I have tried:
return ModelOne::with(['modelTwos.latestModelThree'])
->paginate();
But this is only giving the Model Three for the last Model Two of the last Model One.
All other Model Twos have no Model Three in the response.
The method for latestModelThree on the Model Two class is:
public function latestModelThree()
{
return $this->hasMany(ModelThree::class)
->latest()
->limit(1);
}
Changing larestModelThree() relationship to hasOne() and removing the limit should do the trick:
public function latestModelThree()
{
return $this->hasOne(ModelThree::class)
->latest();
}
It's a little hacky, and don't solve the problem if you need N items of that relationship instead of a single item, but, solves your problem.
The answer by Elias Soares does work but causes major performance issues with large datasets.
A more performant solution is to use this package: https://github.com/staudenmeir/eloquent-eager-limit

Dynamic tables and models in Laravel 5

I have the next tables:
pages
id
title
...
dynamic_table_1_infos
id
page_id
image_id
dynamic_field_1
dynamic_field_2
...
dynamic_table_2_infos
...
So there are "one to many" relationships.
Is there any way to use a general approach without creating a DynamicTable[No]Info model "on the fly" for each table?
And what if I will need some extra methods in these models?
The "Page" model will have many relationships with "dynamic_table_[no]_infos" tables. So I will probably need a general method for doing this.
(Has many dynamic_table_1_infos / has many dynamic_table_2_infos ...)
What I am trying to do is somehow inspired by Dupal`s content types.
If you want to save a single model data to multiple tables depending on the value of some model attribute, you'll need to override model's getTable() method to return the name of the table it should write to.
I'm not sure how you want to decide to which table Eloquent should save to - for example, if you had an attribute called segment in your mode, you could just do:
public function getTable() {
return 'dynamic_table_' . $this->segment . '_infos';
}

Can I use php artisan db:seed to seed related tables?

Is it possible to seed related tables using the following in Laravel 5?
php artisan db:seed
I have two tables
users
id
first name
projects
id
name
and a pivot table
project_user
project_id
user_id
I would like to create a number of users, a number of projects and then relate the users and their respective projects.
Seeding the users and projects isn't a problem but I am not sure how to handle the pivot table.
Is it possible?
Of course you can. If you are using Eloquent, you can simply work with normal relations (maybe the easiest way). Or if you use the SQL builder directly, you can feed the table just as normal, but you need to stick to your foreign key rules.
Just give in a try and you'll see. But make sure you import classes you use.
Adding a relation between two models is easy, but there are some differences between the common relation types (and he perspective): one-to-many, many-to-one and many-to-many.
One-to-Many and Many-to-One
Assumed that each of your project has a creator, an owner so-to-say, you could have a 1:n relation between User and Project.
public class User {
public function ownedProjects() {
return $this->hasMany('App\Project');
}
}
public class Project {
public function owner() {
return $this->belongsTo('App\User');
}
}
In this relation, you can either attach a Project to a User or tell the Project who his owner is.
// Attach a project to an user
$project = Project::create([]);
User::find($id)->ownedProjects()->save($project);
// There is also a function saveMany() for an array of projects
// Tell the project who his owner is
$project = Project::create([]);
$project->owner()->associate(User::find($id));
Many-to-Many
In your case, we need a Many-to-Many relation between Users and Projects. The syntax is a bit different, but the outcome quite straight forward. First we need a relation between the both models:
public class User {
public function projects() {
return $this->belongsToMany('App\Project');
}
}
public class Project {
public function users() {
return $this->belongsToMany('App\User');
}
}
Then we can query the relation just like that:
$project = Project::create([]);
User::find($id)->projects()->attach($project->id);
You can also attach a whole bunch of projects, do the same things from the other side, detach models or synchronize them, if you want to make sure that an exact amount (and only this amount) is in relation:
// Adds a relation for the user to projects with ids 1, 2, 4 and 6
User::find($id)->projects()->attach([1, 2, 4, 6]);
// Adds the users with ids 19 and 173 to this project
Project::find($id)->users()->attach([19, 173]);
// Removes the user 19 from the projects relations
Project::find($id)->users()->detach(19);
// Removes all relations between this user and projects that are
// not listed in the synchronization array and adds a relation
// to all projects where none exists yet
User::find($id)->projects()->sync([4, 7, 19, 6, 38]);
This is the normal syntax for Many-to-Many relations, but you can also attach models just like in a One-to-Many relation:
// Creation of project could also be done before and saved to a variable
User::find($id)->projects()->save(Project::create([]));

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