Q:

"cakephp 3, save not working, Unknown type"

Here is the link CakePHP 3 Saving BelongsToMany Association Unknown type "" Error that I used to first, but could not solve the problem.
I have 3 tables:

Bookings
Travelers
BookingsTravelers

When I save the data in the bookings table I get the error metioned above, see below image:

The models associations look like this:
public function initialize(array $config)
{
    parent::initialize($config);

    $this->table('bookings_travelers');
    $this->displayField('name');
    $this->primaryKey('bPassID');

    $this->belongsTo('Bookings', [
        'foreignKey' => 'booking_id',
        'joinType' => 'INNER'
    ]);
    $this->belongsTo('Travelers', [
        'foreignKey' => 'traveler_id',
        'joinType' => 'INNER'
    ]);
}

public function initialize(array $config)
{

    parent::initialize($config);

    $this->table('bookings');
    $this->displayField('idbooking');
    $this->primaryKey('idbooking');

    $this->belongsTo('Users', [
        'foreignKey' => 'user_id',
        'joinType' => 'INNER'
    ]);

    $this->belongsToMany('Travelers', [
        'joinTable' => 'bookings_travelers',
    ]);
}

public function initialize(array $config)
{
    parent::initialize($config);

    $this->table('travelers');
    $this->displayField('name');
    $this->primaryKey('travelers_id');

    $this->belongsToMany('Bookings', [
        'joinTable' => 'bookings_travelers',
    ]);
}

A:

Basically I had to rename the 'idbooking' to 'id' only after changing the database column name, and it worked. My bad, a silly mistake.

