CakePHP3在同一模型中将表链接在一起（内部联接）

Question

i've a table named 'customers' with following (shortened) schema:

id | customer_id | type | salutation | forename | surname | created | modified

In this table, I want to store people, which are may be associated:

id | customer_id | type    | salutation | forename | surname | created             | modified
 1 | NULL        | husband | Mr.        | John     | Doe     | 2016-01-05 10:00:00 | 2016-01-05 10:00:00
 2 |  1          | wife    | Mrs.       | Jane     | Doe     | 2016-01-05 10:01:00 | 2016-01-05 10:01:00
 3 |  1          | child   | Mr.        | Jim      | Doe     | 2016-01-05 10:02:00 | 2016-01-05 10:02:00

Customers with "customer_id" = NULL are the master customers, but #2 and #3 refers to #1.

I've created the table in phpmyadmin and do: "bin/cake bake all customers" without errors. Then I created the 'master customer'. When I create the second account, I expect that the select-field shows customer #1, but the dropdown-field is empty.

The model:

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

    $this->table('customers');
    $this->displayField('id');
    $this->primaryKey('id');

    $this->belongsTo('Customers', [
        'foreignKey' => 'customer_id',
        'joinType' => 'INNER'
    ]);
    $this->hasMany('Customers', [
        'foreignKey' => 'customer_id'
    ]);
}

If you need further information or more piece of code, let me know.
Many thanks in advance.

best regards
Martin

---

SQL to reproduce

CREATE TABLE IF NOT EXISTS `customers` (
  `id` int(11) NOT NULL,
  `typ` varchar(10) NOT NULL,
  `customer_id` int(11) DEFAULT NULL,
  `salutation` varchar(4) NOT NULL,
  `prename` varchar(255) NOT NULL,
  `surname` varchar(255) NOT NULL,
  `created` datetime NOT NULL,
  `modified` datetime NOT NULL
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=latin1;

INSERT INTO `customers` (`id`, `typ`, `customer_id`, `salutation`, `prename`, `surname`, `created`, `modified`) VALUES
(1, 'husband', NULL, 'Mr.', 'John', 'Doe', '2016-03-02 21:26:32', '2016-03-02 21:26:32'),
(2, 'wife', 1, 'Ms.', 'Jane', 'Doe', '2016-03-02 21:27:25', '2016-03-02 22:10:05'),
(3, 'child', 1, 'Mr.', 'Jim', 'Doe', '2016-03-02 21:27:41', '2016-03-02 22:10:15');

ALTER TABLE `customers` ADD PRIMARY KEY (`id`), ADD KEY `customers_fk0` (`customer_id`);
ALTER TABLE `customers` MODIFY `id` int(11) NOT NULL AUTO_INCREMENT,AUTO_INCREMENT=4;
ALTER TABLE `customers` ADD CONSTRAINT `customers_fk0` FOREIGN KEY (`customer_id`) REFERENCES `customers` (`id`);

Than, run

bin/cake bake all customers

---

EDIT I've checked, the possible duplicate , and changed my model

$this->belongsTo('Customers', [
    'foreignKey' => 'customer_id',
    'joinType' => 'INNER'
]);
$this->hasMany('ChildCustomers', [ // <-- changed this line
    'className' => 'Customers',    // <-- added this line
    'foreignKey' => 'customer_id'
]);

Now, if I try to add/edit, no changes to the select. But if I view an existing customer, i got:

Error: SQLSTATE[42000]: Syntax error or access violation: 1066 Not unique table/alias: 'Customers'

This is the code for displaying the select:

echo $this->Form->input('customer_id');

This code was genereated by "bin/cake bake all customers"

---

EDIT 2

I'll will summarize my current state:

Model:

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

    $this->table('customers');
    $this->displayField('id');
    $this->primaryKey('id');

    $this->belongsTo('ParentCustomers', [
        'className' => 'Customers',
        'foreignKey' => 'customer_id',
        'joinType' => 'INNER'
    ]);
    $this->hasMany('ChildCustomers', [
        'className' => 'Customers',
        'foreignKey' => 'customer_id'
    ]);
}

public function buildRules(RulesChecker $rules)
{
    $rules->add($rules->existsIn(['customer_id'], 'ParentCustomers'));
    return $rules;
}

Controller:

public function view($id = null)
{
    $customer = $this->Customers->get($id, [
        'contain' => ['ParentCustomers']
    ]);

    $this->set('customer', $customer);
    $this->set('_serialize', ['customer']);
}

If an user has an association (wife, child), the view displays a headline "Related Customers" on bottom of the page, but no additional table which shows the related customers. If an user has "customer_id = 0", the view said 'Record not found in table "customers"'.

I've also added

$this->set('customers', $this->Customers->find('list'));

to the add() and edit() function, but I found no way to allow also an empty value.

For clarification: Later, the front page (index()) should only list the "master customer" with customer_id = 0 with a small nested table, if he have a wife and/or children.

I think I am on the right way... Am I?

Thanks again in Advance

Answer 1

You should also use ParentCustomers for the first association. Customers duplicates itself.

$this->belongsTo('ParentCustomers', [ // <-- You need to change here
    'className' => 'Customers', // <-- You need to change here
    'foreignKey' => 'customer_id',
    'joinType' => 'INNER'
]);
$this->hasMany('ChildCustomers', [
    'className' => 'Customers',
    'foreignKey' => 'customer_id'
]);

Answer 2

Are you sure you did load the model already in the controller?

Put following into controller's initialize() : $this->loadModel('Customers');

EDIT: So it's like:

    public function initialize()
    {
        parent::initialize();

        $this->loadModel('Customers');
    }

Answer 3

I've solved the issue by using CakePHPs TreeBehavior .

I use parent_id instead of customer_id and added rght and lft column as discribed in Blog Tutorial - Part 3 .

It is working for me now! Thanks everyone!