Laravel Eloquent Relationship with 4 tables (3 model + 1 table) - laravel

Question

Hi I have this 4 tables
Employee:
EmployeeID,
EmployeeName,
EmployeeEmail,
EmployeePassword
Department:
DepartmentID,
DepartmentName
Position:
PositionID,
PositionType
employee_deployment:
EmployeeDeploymentID,
EmployeeID,
DepartmentID,
PositionID
I created a migration for a Pivot table employee_deployment
public function up()
{
// Set schema to create field of table
Schema::create('employee_deployment', function (Blueprint $table) {
$table->bigIncrements('EmployeeDeploymentID');
$table->bigInteger('EmployeeID')->unsigned();
$table->bigInteger('DepartmentID')->unsigned();
$table->bigInteger('PositionID')->unsigned();
});
Schema::table('employee_deployment', function ($table) {
$table->foreign('EmployeeID')->references('EmployeeID')->on('tbl_employees')->onDelete('cascade');
$table->foreign('DepartmentID')->references('DepartmentID')->on('tbl_departments')->onDelete('cascade');
$table->foreign('PositionID')->references('PositionID')->on('positions')->onDelete('cascade');
});
}
Can someone help me to create a relationship for each model? And save the data into pivot table (employee_deployment table).

Answer 1

A pivot table cannot be used in this way to define 2 relationships at once, instead I would recommend having a Deployment model which has a one to one relationship with the other three models.
class Deployment extends Model
{
public function employee()
{
return $this->hasOne('App\Employee');
}
public function department()
{
return $this->hasOne('App\Department');
}
public function position()
{
return $this->hasOne('App\Position');
}
}
class Employee extends Model
{
public function deployment()
{
return $this->belongsTo('App\Deployment');
}
}
class Position extends Model
{
public function deployment()
{
return $this->belongsTo('App\Deployment');
}
}
class Department extends Model
{
public function deployment()
{
return $this->belongsTo('App\Deployment');
}
}
If you want to be able to access the relationships between Employee and Position or Position and Department or Employee and Department directly you can also add hasOneThrough relationships to the other 3 models
public function employee()
{
return $this->hasOneThrough('App\Employee', 'App\Deployment');
}
public function department()
{
return $this->hasOneThrough('App\Department', 'App\Deployment');
}
public function position()
{
return $this->hasOneThrough('App\Position', 'App\Deployment');
}
I think this should get you the relationships you're looking for
If any of these relationships aren't 1 to 1 then you'll need pivot tables between Deployment and the other 3 models but you should be able to just switch hasOneThrough to hasManyThrough to keep the direct relationships
For your migrations, if you don't use regular id columns on the employee, department, and position models you'll have to add a custom foreign key definition to the relationships. As an example the one for Deployment->Employee would be
public function employee()
{
return $this->hasOne('App\Employee', 'EmployeeID', 'EmployeeID');
}