I'm working on a Laravel installation where I have (among other things)
Teachers (table:users (cols: id, name, type), model:User, users.type = 2)
Students (table:users (id, name, type), model:User, users.type = 1)
Schools (table:schools (id, name), model:School)
Collections of students (table:student_collection (id, name), model:StudentCollection)
& table student_collections_users for linking the student-users to collections (model: StudentsCollections, columns id, user_id, collection_id)
I have managed to setup some relationships, but can't get my head around to get
Which teachers teach a student
Which collections does a student belong to
Currently I'm trying to get the collections with
//User.php
public function collections() {
$collection = $this->hasManyThrough('\App\StudentsCollections', '\App\User', 'id', 'user_id');
return $collection;
}
//Controller
$user = \App\User::find($id);
$user->collections = $user->collections();
but it only returns the id's of the collections. How can I get the full data object for each collection?
I'm using Laravel 5.3.
First, In your example code, are the table names correct?
I see a table called 'students_collections', but your belongsToMany has a table name (second param) 'student_collections_users'. That's a typo, I presume.
Second, what does return an empty result? Calling the collections method or the collections property on the User model? Can you add some sample code?
Third: you have actual data in the database (through a seeder or real data)? I know this is obvious, but sometimes people tend to forget the obvious... :-)
Related
I have users and user_roles tables, and id of user_roles is used as foreign key in users. I fetched data from users using User::with('userRole')->find($user). In returned result userRole is present, however it is empty, instead it was supposed to have data from user_roles for the particular foreign key.
Please, share what can be the possible issues with the functionality or if anyone can explain working of laravel associations in brief.
/* User Model */
public function userRole()
{
return $this->belongsTo('App\UserRole');
}
/* UserRole Model */
public function user()
{
return $this->hasMany('App\User');
}
Thank You,
Many to many relationships in Laravel often require you to have 2 models and 3 tables. One to many relationships require you to have 2 models and 2 tables. One to one relationship also requires you to have 2 models and 2 tables.
Many to many relationship
Let's take User and Role models, since each User can have multiple roles and one Role can be assigned to different users, you will naturally want a Many to many relationship. Now, you will need to create an intermediate table in which you will store the results, why? Because you already defined both User and Role and since it is Many to many none of those objects will have any identifier of the other one inside of them, but rather will have their own identifier in the intermediate table, and this is how Laravel fetches the relationship, it connects Models primary key with foreign key inside of the intermediate table.
One to many relationships
Let's take User and Role models again and let's say that this time, one Role can be assigned to multiple users, but one User can ONLY have 1 Role. Naturally you will have a field role_id inside of your User model and you will connect role_id from users with id from roles.
One to one relationships
Lets take User and Role models again :D Let's say you want to create a separate Role for every user, then you will have 2 models and 2 tables where your users table will have all the users and your roles table will contain id, name, user_id and now when you try to retrieve the relationship, if you define one to one laravel will return only 1 result, no matter if you have multiple same user_id on the roles table, Laravel will return only 1 role because you told him explicitly it's 1-to-1 relationship.
EDIT:
Here is an example of one to one relationship:
/* User Model */
public function userRole()
{
return $this->belongsTo('App\UserRole', 'user_role_id', 'id');
}
#Tim and #Nikola
Thank you, for your efforts mates.
However, I found the reason behind the problem. It was because the wrong naming of userRole function in User model.
I was using foreign key of user_roles as user_roles_id in users table and defined function with name of userRole in User model. This leads to ORM not found the relevant column for attaching user_roles data.
The solution is either I have to change the name of user_roles_id to user_role_id or userRole function name to userRoles. And I choose the first one and it worked fine. :)
For reference on the naming conventions of laravel please refer to Laravel - Database, Table and Column Naming Conventions?.
I'm trying to get 'related' linked models by querying a link table, named company_projects which holds (as you expect) the id's of companies and projects (projects are kind of product-categories).
In this case, the used flow to determine a related project is:
Get companies who are in the same project ('product category') as you
Find the other project id's which are linked to those companies
Get the info of the linked projects fetched by last step
What i'm trying to do is already functional in the following raw query:
SELECT
*
FROM
projects
WHERE
projects.id IN
(
SELECT cp1.project_id
FROM company_projects cp1
WHERE cp1.company_id IN
(
SELECT cp1.company_id
FROM projects p
LEFT JOIN company_projects cp2 ON cp2.project_id = p.id
WHERE p.id = X AND cp2.company_id != Y
)
)
AND projects.id != X
X = ID of current project ('product category')
Y = ID of current 'user' (company)
But my real question is, how to do this elegantly in Laravel Eloquent (currently v4.2). I tried it, but I have no luck so far...
Update:
I should note that I do have experience using Eloquent and Models through multiple projects, but for some reason I just fail with this specific query. So was hoping to see an explained solution. It is a possibility that I'm thinking in the wrong way and that the answer is relatively easy.
You will need to utilize Eloquent relationships in order to achieve this. (Note that I am linking to the 4.2 docs as that is what you are using, but I would highly suggest upgrading Laravel to 5.1)
I am assuming you have a 'Company' and 'Project' model already. Inside each of those models, you need to a define a method that references its relationship to the other model. Based on your description, it sounds like the two have a Many to Many relationship, meaning that a company can have many projects and a project can also belong to many companies. You already have a database table linking the two. In the Eloquent ORM this linking table is called a pivot table. When you define your relationships in the model, you will need to pass the name of that pivot table as your second argument. Here's how it could look for you.
Company model:
class Company extends Model
{
/**
* Get the projects attached to a Comapny. Many To Many relationship.
*/
public function projects()
{
return $this->belongsToMany('Project','company_projects');
}
}
Project model:
class Project extends Model
{
/**
* Get the companies this project belongs to. Many To Many relationship.
*/
public function companies()
{
return $this->belongsToMany('Company','company_projects');
}
}
If your models have these relationships defined, then you can easily reference them in your views and elsewhere. For example, if you wanted to find all of the projects that belong to a company with an ID of 1234, you could do this:
$company = Company::find(1234);
$projects = $company->projects;
Even better, you can utilize something called eager loading, which will reduce your data lookup to a single line (this is mainly useful when passing data to views and you will be looping over related models in the view). So those statements above could be rewritten as:
$company = Company::with('projects')->find(123);
This will return your Company model with all its related products as a property. Note that eager loading can even be nested with a dot notation. This means that you can find all the models that link to your main model, and then all the models for those models, and so on and so forth.
With all of this in mind, let's look at what you specifically want to accomplish.
Let us assume that this method occurs in a Controller that is being passed a project id from the route.
public function showCompaniesAndProjects($id)
{
//Get all companies in the same project as you
//Use eager loading to grab the projects of all THOSE companies
//Result will be a Project Object with all Companies
//(and those projects) as Eloquent Collection
$companies = Project::with('companies.projects')->find($id);
//do something with that data, maybe pass it to a view
return view('companiesView')->with('companies',$companies);
}
After defining your relations in your models, you can accomplish that whole query in a single line.
I have two tables:
treatments (
id,
name
)
companies (
id,
name
)
And I need to build a relation to a "price" table. I thougth in something like follows:
prices (
treatment_id,
company_id,
price
)
But i don know how to apply the ORM to a php aplication. I'm using Laravel with Eloguent's ORM. I think that the real question would be if this is a good way to design the db. Perhaps I should make it diferent?
Any advices?
Thanks,
Ban.
If a Company can have multiple Treatments and a treatment can be bought from multiple companies at different prices, then you have a Many-to-many relationship, with prices being the pivot table (which if you would adhere to convention would be named company_treament, but that's not a must). So you'll need to have two models for Treatments and Companies, which would look like this:
class Company extends \Eloquent {
public function treatments()
{
return $this->belongsToMany('Treatment', 'prices')->withPivot('price');
}
and
class Treatment extends \Eloquent {
public function companies()
{
return $this->belongsToMany('Company', 'prices')->withPivot('price');
}
}
The treatments() and companies() methods from the models are responsible for fetching the related items. Usually the hasMany method only requires the related model as the first parameter, but in your case the pivot table name is non-standard and is set to prices by passing it as the second parameter. Also normally for the pivot table only the relation columns would be fetched (treatment_id and company_id) so you need to specify the the extra column using withPivot. So if you want to get the treatments for a company with the id 1 list you whould to something like this:
$treatments = Company::find(1)->treatments;
The opposite is also true:
$companies = Treatment::find(1)->companies;
If you need to access the price for any of those relations you can do it like this:
foreach ($treatments as $treatment)
{
$price = $treatment->pivot->price;
}
You can read more about how to implement relationships using Eloquent in the Laravel Docs.
EDIT
To insert a relation entry in the pivot table you can use attach and to remove one use detach (for more info read the Docs).
$treatment->companies()->attach($companyId, array('price' => $price));
$treatment->companies()->detach($companyId);
To update a pivot table entry use updateExistingPivot:
$treatment->companies()->updateExistingPivot($companyId, array('price' => $price));
I have two tables in MySQL, where the first one is called users and the second one is called games. The table structure is as follows.
users
id (primary)
email
password
real_name
games
id (Primary)
user_one_id (foreign)
user_one_score
user_two_id (foreign)
user_two_score
My games table is holding two foreign relations to two users.
My question is how do I make the model relations for this table structure?? - According to the laravel documentation, I should make a function inside the model and bind it with its relations
for instance
public function users()
{
$this->belongsTo('game');
}
however I can't seem to find anything in the documentation telling me how to deal with two foreign keys. like in my table structure above.
I hope you can help me along the way here.
Thank you
A migration:
$table->integer('player1')->unsigned();
$table->foreign('player1')->references('id')->on('users')->onDelete('cascade');
$table->integer('player2')->unsigned();
$table->foreign('player2')->references('id')->on('users')->onDelete('cascade');
And a Model:
public function player1()
{
$this->belongsTo('Game', 'player1');
}
public function player2()
{
$this->belongsTo('Game', 'player2');
}
EDIT
changed 'game' to 'Game' as user deczo suggested.
Unfortunately the way you have this setup is not likely to work in the current context. You may have more luck with the belongsTo method, but again that only supports one relationship.
You could implement a user1() belongsTo, a user2() belongsTo and finally just declare a non eloquent function to return both (something like $users = array($this->user1(), $this->user2())
I'm trying to create a polymorphic relationship with multiple pivot tables. I have a table of requirements that can be assigned to accounts, roles, trips, and countries. This needs to be a many to many relationship because the same requirement could apply to multiple countries and/or trips and/or accounts etc.
I then need a table listing outstanding requirements for the user. For example: if a user has a certain account and there are requirements related to that account, then those requirements would be added to the user's list of requirements.
One solution I have is to first assign the requirements to the accounts, roles, trips, and countries using Pivot tables in a Many to Many relationship. Then using a polymorphic relationship I would connect the user to whichever pivot tables relate.
But I don't know how to do this or if it is even possible?
Here are my tables:
user_requirements
- id
- user_id
- requireable_id
- requireable_type
account_requirement
- id
- account_id
- requirement_id
role_requirement
- id
- role_id
- requirement_id
trip_requirement
- id
- account_id
- requirement_id
country_requirement
- id
- account_id
- requirement_id
Laravel 4.1 now has support for polymorphic many to many relationships.
Example below shows how I have implemented sharing Photos with both Products and Posts.
DB Schema
photos
id integer
filename string
alt string
photoable
id integer
photoable_id integer
photoable_type string
Models
Photo Model
class Photo extends Eloquent
{
public function products(){
return $this->morphedByMany('Product', 'photoable');
}
public function posts(){
return $this->morphedByMany('Post', 'photoable');
}
}
Product Model
class Product extends Eloquent
{
public function photos(){
return $this->morphToMany('Photo', 'photoable');
}
}
Post Model
class Post extends Eloquent
{
public function photos(){
return $this->morphToMany('Photo', 'photoable');
}
}
With the above, I can access all photos which are attached to a product as follows:
$product = Product::find($id);
$productPhotos = $product->photos()->all();
I can also iterate over to display all photos as any collection of models.
foreach ($productPhotos as $photo)
{
// Do stuff with $photo
}
The above can be replicated almost exactly to your requirements.
create a requirements table
create a requireable table
In Requirement model, declare all morphedByMany relationships
In Country, Trip, Role etc. declare morphToMany relationships
nb - I've typed this out freehand in S/O with no code editor, so there will probably be a typo, error or two - but concept remains the same.
A polymorphic relation in Laravel 4 is intended for single MODEL associations, therefore you cannot achieve what you are trying to build with this method. This is due to the fact that a pivot table doesn't represent a Model.