MODEL:
class TableasTable extends Table
{
    /**
     * Initialize method
     *
     * @param array $config The configuration for the Table.
     * @return void
     */
    public function initialize(array $config)
    {
        parent::initialize($config);

        $this->setTable('tableas');
        $this->setDisplayField('name');
        $this->setPrimaryKey('id');

        $this->addBehavior('Timestamp');

        $this->hasMany('tablebs', [
            'foreignKey' => 'tablea_id',
            'bindingKey' => 'id',
        ]);
    }

    /**
     * Default validation rules.
     *
     * @param \Cake\Validation\Validator $validator Validator instance.
     * @return \Cake\Validation\Validator
     */
    public function validationDefault(Validator $validator)
    {
        $validator
            ->integer('id')
            ->allowEmptyString('id', null, 'create');

        $validator
            ->scalar('name')
            ->maxLength('name', 22)
            ->requirePresence('name', 'create')
            ->notEmptyString('name');

        return $validator;
    }
}

Query:
   $ordersTable = TableRegistry::getTableLocator()->get('Tableas');
        $q = $ordersTable->find('all',['contain'=>['Tablebs']])->execute();
               print_r($q);
Generated querystring:
[queryString] => SELECT Tableas.id AS `Tableas__id`, Tableas.name AS `Tableas__name`, Tableas.modified AS `Tableas__modified`, Tableas.created AS `Tableas__created` FROM tableas Tableas

If I change the model relation to hasOne (the query code is left as is), the generated querystring becomes:

[queryString] => SELECT Tableas.id AS `Tableas__id`, Tableas.name AS `Tableas__name`, Tableas.modified AS `Tableas__modified`, Tableas.created AS `Tableas__created`, tablebs.id AS `tablebs__id`, tablebs.tablea_id AS `tablebs__tablea_id`, tablebs.name AS `tablebs__name`, tablebs.created AS `tablebs__created`, tablebs.modified AS `tablebs__modified` FROM tableas Tableas LEFT JOIN tablebs tablebs ON Tableas.id = (tablebs.tablea_id)


What am I missing/ doing wrong in case of the hasMany relation?