I'm trying to create a relationship between two tables using Eloquent belongsTo but it doesn't seem to work.
the two tables are documents and departments , each document belongs to one department.
documents
id INT
department INT
departments
id INT
name varchar(255)
this is the function that defines the relationship
public function department(){
// department: foreign key
// id : departments table primary key
return $this->belongsTo('\App\Department' , 'department' , 'id');
}
and this is the accessor function
public function getDepartmentAttribute(){
return $this->department()->first()->name;
}
it returns the following error message: Undefined property: App\AjaxSearch::$department
In documents table add
department_id INT Foreign
In your documents migration
$table->integer('department')->unsigned();
Also edit the relationship
public function department() {
return $this->belongsTo('App\Department', 'department');
}
Update
Ok according to your updates, you can get the department name like this
$doc = Document::find(1);
$name = $doc->department->name;
You need to check whether the related record exists
public function department()
{
return $this->belongsTo('App\Department', 'department');
}
$document is your current document record.
$name = (empty($document->department->id) === false) ? ($document->department->name) : '';
Related
I have a ManyToMany relationship between Election and Party to connect parties to multiple elections.
public function parties(): BelongsToMany
{
return $this
->belongsToMany(Party::class)
->using(ElectionParty::class)
->withPivot('has_no_answers', 'published', 'program_pdf', 'program', 'id');
}
On the pivot table election_party I added an auto incrementing id.
Parties can give answers to each election, for which reason I created a hasMany relationship to Answer on the pivot table, referenced by electionparty_id
class ElectionParty extends Pivot
{
public function answers(): HasMany
{
return $this->hasMany(Answer::class);
}
}
Now, to get the answers or in this case it's count, i do this in Blade:
#foreach($election->parties as $party)
{{ $party->pivot->answers->count() }}
#endforeach
This however, does not work, because it does not try to get answers by the pivot table id, which I assumed it would be but by the id of the election:
SQLSTATE[42703]: Undefined column: 7 ERROR: column answers.election_id does not exist LINE 1: select * from "answers" where "answers"."election_id" = $1 a... ^ HINT: Perhaps you meant to reference the column "answers.question_id". (SQL: select * from "answers" where "answers"."election_id" = 16 and "answers"."election_id" is not null)
Am I missing something here or doing something not how it's supposed to be done?
The default keys are generated differently in pivot models. Specify the foreign key:
class ElectionParty extends Pivot
{
public function answers(): HasMany
{
return $this->hasMany(Answer::class, 'electionparty_id');
}
}
So im creating a booking system where you can create maps and assign them to an event. I have 3 tables to handle this, events, maps, and event_maps
I have after reading the Laravel Documentation i decided to set up a belongsToMany relation.
But when i try to retrieve my maps thru my event model i only get one the first row.
in my controller i do
public function displayForm($id)
{
$event = EventModel::find($id);
print_r($event->maps);
}
The result is a Illuminate\Database\Eloquent\Collection Object with the last out of 2 maps, and i can't for my life figger out how to get them all.
My EventsModel
public function maps()
{
return $this->belongsToMany('App\Models\Booky\MapsModel',
// Table name of the relationship's joining table.
'event_maps',
// Foreign key name of the model on which you are defining the relationship
'map_id',
// Foreign key name of the model that you are joining to
'event_id'
);
}
My MapsModel
public function event()
{
return $this->belongsToMany('App\Models\Booky\EventsModel',
// Table name of the relationship's joining table.
'event_maps',
// Foreign key name of the model on which you are defining the relationship
'event_id',
// Foreign key name of the model that you are joining to
'map_id'
);
}
The database looks something like this
events
- id
- lots of irrelevant data
maps
- id
- lots of irrelevant data
event_maps
- id
- event_id
- map_id
I was thinking that perhaps i should use another relation type, but as far as i understand they don't use a relation table like event_maps.
Everything else work as expected.
Anyone who could clear up this mess? :)
The ids are inverted in the relation. Try this:
public function maps()
{
return $this->belongsToMany('App\Models\Booky\MapsModel',
// Table name of the relationship's joining table.
'event_maps',
// Foreign key name of the model that you are joining to
'event_id'
// Foreign key name of the model on which you are defining the relationship
'map_id',
);
}
And:
public function event()
{
return $this->belongsToMany('App\Models\Booky\EventsModel',
// Table name of the relationship's joining table.
'event_maps',
// Foreign key name of the model that you are joining to
'map_id'
// Foreign key name of the model on which you are defining the relationship
'event_id',
);
}
i have two tables as below:
users table:
|id|name|email|password|created_at|updated_at
messages table:
|id|sender_id|receiver_id|message|created_at|updated_at
User model:
public function threads()
{
return $this->hasManyThrough(Message::class, User::class,'id','sender_id');
}
i'm trying retrieve message threads
which isn't working. any help appreciated.
This is an example from laravel eloquent relationship
class Country extends Model
{
public function posts()
{
return $this->hasManyThrough(
'App\Post',
'App\User',
'country_id', // Foreign key on users table...
'user_id', // Foreign key on posts table...
'id', // Local key on countries table...
'id' // Local key on users table...
);
}
}
can you review your code
It seems that you want to retrieve all messages that belongs to a single thread (list of users) using hasMany relationship Through User model, to do that You have to define hasManyThrough inside Thread model not in User model, here is an example:
User:
|id|name|email|password|created_at|updated_at|thread_id
Note thread_id foreign key because thread is a list of users
Thread:
class Thread extends Model {
public function messages() {
return $this->hasManyThrough(Message::class, User::class,'thread_id','sender_id', 'id', 'id');
}
}
Example from laravel doc
I've got a strange problem.
I've a users table and a company table. A User belongsTo a company and a company hasMany users.
Both primary keys of the table are id.
In the laravel documentation I read the following:
Additionally, Eloquent assumes that the foreign key should have a
value matching the id column of the parent.
I've got this in my CompanyModel:
protected $table = 'company';
public function users()
{
return $this->hasMany(UserModel::class);
}
When I try this:
$users = CompanyModel::find(1)->users;
dd($users);
It's not working. When I add a foreign key in my relation it works!?:
protected $table = 'company';
public function users()
{
return $this->hasMany(UserModel::class, 'id');
}
This is strange right? What on earth am I doing wrong.
--EDIT--
In my users table I've got a company_id column!
Firstly, I would suggest you rename your Model from CompanyModelto Company and from UserModel to User.
Then ensure you have company_id in your users table. And in your users migration file connect the users table with the companies table as such:
$table->integer('company_id')->unsigned();
$table->foreign('company_id')->references('id')->on('companies')->onDelete('cascade');
Don't forget to refresh your database.
Then in your models, define the relationships as such:
// User model
// Laravel will automatically identify and use the `company_id` field in your reference
public function company(){
return $this->belongsTo(Company::class);
}
// Company model
public function users(){
return $this->hasMany(User::class);
}
You can then fetch your records in your controller as such:
$user = User::find(1);
$user_company = $user->company; // This might not be necessary in your controller, you can do it in your view
dd($users, $user_company);
So the belongsToMany relationship is a many-to-many relationship so a pivot table is required
Example we have a users table and a roles table and a user_roles pivot table.
The pivot table has two columns, user_id, foo_id... foo_id referring to the id in roles table.
So to do this we write the following in the user eloquent model:
return $this->belongsToMany('Role', 'user_roles', 'user_id', 'foo_id');
Now this looks for an id field in users table and joins it with the user_id field in the user_roles table.
Issue is I want to specify a different field, other than id to join on in the users table. For example I have bar_id in the users table that I want to use as the local key to join with user_id
From laravel's documentation, it is not clear on how to do this. In other relationships like hasMany and belongsTo we can specify local key and foriegn key but not in here for some reason.
I want the local key on the users table to be bar_id instead of just id.
How can I do this?
Update:
as of Laravel 5.5 onwards it is possible with generic relation method, as mentioned by #cyberfly below:
public function categories()
{
return $this->belongsToMany(
Category::class,
'service_categories',
'service_id',
'category_id',
'uuid', // new in 5.5
'uuid' // new in 5.5
);
}
for reference, previous method:
I assume id is the primary key on your User model, so there is no way to do this with Eloquent methods, because belongsToMany uses $model->getKey() to get that key.
So you need to create custom relation extending belongsToMany that will do what you need.
A quick guess you could try: (not tested, but won't work with eager loading for sure)
// User model
protected function setPrimaryKey($key)
{
$this->primaryKey = $key;
}
public function roles()
{
$this->setPrimaryKey('desiredUserColumn');
$relation = $this->belongsToMany('Role', 'user_roles', 'user_id', 'foo_id');
$this->setPrimaryKey('id');
return $relation;
}
On Laravel 5.5 and above,
public function categories()
{
return $this->belongsToMany(Category::class,'service_categories','service_id','category_id', 'uuid', 'uuid');
}
From the source code:
public function belongsToMany($related, $table = null, $foreignPivotKey = null, $relatedPivotKey = null,
$parentKey = null, $relatedKey = null, $relation = null)
{}
This is a recently added feature. I had to upgrade to 4.1 because I was also looking for this.
From the API documentation:
public BelongsToMany belongsToMany(string $related, string $table = null, string $foreignKey = null, string $otherKey = null, string $relation = null)
The $otherKey and $relation parameters were added in 4.1. Using the $foreignKey and $otherKey parameters allows you to specify the keys on both sides of the relation.
The best way is set the primary key.
class Table extends Eloquent {
protected $table = 'table_name';
protected $primaryKey = 'local_key';
belongsToMany allows to define the name of the fields that are going to store che keys in the pivot table but the method insert always the primary key values into these fields.
You have to:
define in the method belongsToMany the table and the columns;
then using protected $primaryKey = 'local_key'; you can choose which value store.
I recently went through the same problem where I needed to have an associated table that used ID's to link two tables together that were not Primary Keys. Basically what I did was create a copy of my model that models the pivot table and set the Primary Key to the value that I wanted it to use. I tried creating a model instance, settings the primary key and then passing that to the relation but Laravel was not respecting the primary key I had set ( using the ->setPrimaryKey() method above ).
Making a copy of the model and setting the primary key feels a little bit 'hackish' but in the end it works as it should and since Pivot table models are generally very small I don't see it causing any problems in the future.
Would love to see a third key option available in the next release of Laravel that lets you get more specific with your linking.