SQLSTATE[23000]: Integrity constraint violation 1452 Cannot add or update a child row: a foreign key constraint fails

Question

I have this migration file

class AddRolesFieldsToUsersTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::table('users', function (Blueprint $table) {
            $table->foreignId('role_id')->constrained();
            $table->string('student_address')->nullable();
            $table->string('student_licence_number')->nullable();
            $table->string('teacher_qualifications')->nullable();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::table('users', function (Blueprint $table) {
            //

And a User model has all fillables like seen below

class User extends Authenticatable
{
    use HasApiTokens;
    use HasFactory;
    use HasProfilePhoto;
    use Notifiable;
    use TwoFactorAuthenticatable;

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        'name',
        'email',
        'password',
        'role_id',
        'student_address',
        'student_licence_number',
        'teacher_qualifications',
    ];

But I get the SQLSTATE[23000]: Integrity constraint violation 1452 Cannot add or update a child row: a foreign key constraint fails when I try to register a new user, how should I fix this?

Answer 1

To solve this, manually insert the roles value into the database.

So for the first row:

id=2 | name=Teacher | created_at =0000-00-00 00:00:00|updated_at 0000-00-00 00:00:00

Second row:

id=3 | name=Student| created_at =0000-00-00 00:00:00|updated_at 0000-00-00 00:00:00