Difference between setting ID directly and setting eloquent associate relation when saving a model in Laravel?

Question

I have two tables, employees and employee types.

employees has the following fields

• id (PK)
• employee_type_id (FK)
• name

and employee_type has the following fields,

• id (PK)
• title

My eloquent model functions are,

Employee

  class Employee extends Model {

    public function employeeTypes() {
        return $this->belongsTo('App\Model\EmployeeType');
    }
}

EmployeeType

class EmployeeType extends Model {
}

I am not sure if this is the correct way to keep a relation. While inserting I can follow these two methods:

1.Setting ID

 $emp = new Employee();
 $emp->employee_type_id = $request->type_id;
 $emp->name = $request->name;
 $emp->save();

2.Setting relation

$emp->employeeTypes()->associate(EmployeeType::findOrFail($request->employee_types_id));
$emp->name = $request->name;
$emp->save();

Both methods are working fine.

What is the difference between these two types of insertion?

Which is best method?

Answer 1

Before I compare the options, there is a third one:

Using associate() with just the id

$emp->employeeTypes()->associate($request->employee_types_id);

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Now let's see what the advantages and disadvantages of the methods are:

1. Setting the foreign key manually

• Pro: It's the simplest method
• Contra: You have to explicitly use the foreign key column name

2. Using associate() with the model

• Pro: The relationship will be set automatically so you can use the model later without first fetching it from the database
• Pro: The name of the foreign key column doesn't matter (it only needs to be defined in the relationship declaration)
• Contra: An extra query is necessary to fetch the related model first

3. Using associate() with just the id

• Pro: The name of the foreign key column doesn't matter (it only needs to be defined in the relationship declaration)
• Contra: The relationship won't be loaded after associating the id. A query will run when you access $emp->employeeTypes

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I personally prefer to use associate() (basically all relationship methods, even if they aren't always necessary). If I already have the model I pass that, and otherwise I'll just use the id. You already have defined your relationship with foreign key etc, so you might as well use it.