PHP / Laravel VIII (Eloquent)

Relationship between tables

Create the father table

• php artisan mak:mig create_migration_card_table --create=cards

Create the child table

• php artisan mak:mig create_migration_card_table --create=notes

Relationship

Create the foreign key in the child table

• $table->integer('card_id')->unsigned()->index(); 

Create the Model

• php artisan make:model Note
• php artisan make:model Card

Shortcut

In this way we can create the model and the migration at the same time

• php artisan make:model <Class> -m

Refresh DB

• php artisan migrate:refresh 

Using Eloquent

In the father class (Model) add a method to get the childs

• public function notes(){
•         
•         return $this->hasMany( <Class>::class );
•         
•     }

In the child class (Model) add the next method to get the father

 public function card(){
     
        return $this->belongsTo(Card::class);
     
    }

With this method we can relate a child more easily in tinker as:

• $card->notes()->save($note);

Using Tinker

Get in a variable the registers of a table

• $card =  App\Card::first();

Get all the results and then get the first

• $card->notes->first();

Get the first result

• $card->notes()->first();

Display the SQL commands that internally use tinker

• DB::listen( function($query) { var_dump($query->sql); }  ) ;
• Use fresh() if the query has been done due to Tinker save the query
• $card->fresh()->notes->first();