Cakephp 3 EmiratesToMany导致未定义的偏移量/索引

Question

I have "Groups" and "Servers" tables that i need to join through many to many relationship. I created third table in database "mn_groups_servers" with columns id , group_id and server_id . I added to GroupsTable:

    public function initialize(array $config) {
    parent::initialize($config);
    $this->table('mn_groups');

    $this->belongsToMany('Servers', [
        'joinTable' => 'mn_groups_servers',
        'foreignKey' => 'group_id',
        'targetForeignKey' => 'server_id',
    ]);

}

And to ServersTable:

    public function initialize(array $config) {
    parent::initialize($config);        
    $this->table('mn_servers');

    $this->belongsToMany('Groups', [
        'joinTable' => 'mn_groups_servers',
        'foreignKey' => 'server_id',
        'targetForeignKey' => 'group_id',
    ]);
}

Then in GroupsController i try to fetch the results with:

    public function index() {
    $groups = $this->Groups->find('all')->contain('Servers');
    $this->set(compact('groups'));
}

This results in two errors:

Notice (8): Undefined offset: 0 [CORE\src\ORM\Association\SelectableAssociationTrait.php, line 286]

Cake\ORM\Association\BelongsToMany::_resultInjector() - CORE\src\ORM\Association\SelectableAssociationTrait.php, line 286
Cake\ORM\Association\BelongsToMany::eagerLoader() - CORE\src\ORM\Association\SelectableAssociationTrait.php, line 57
Cake\ORM\EagerLoader::loadExternal() - CORE\src\ORM\EagerLoader.php, line 542
Cake\ORM\Query::_execute() - CORE\src\ORM\Query.php, line 657
Cake\ORM\Query::_all() - CORE\src\Datasource\QueryTrait.php, line 218
Cake\ORM\Query::all() - CORE\src\ORM\Query.php, line 608
Cake\ORM\Query::getIterator() - CORE\src\Datasource\QueryTrait.php, line 132
include - APP/Template\Groups\index.ctp, line 10
Cake\View\View::_evaluate() - CORE\src\View\View.php, line 834
Cake\View\View::_render() - CORE\src\View\View.php, line 794
Cake\View\View::render() - CORE\src\View\View.php, line 465
Cake\Controller\Controller::render() - CORE\src\Controller\Controller.php, line 582
Cake\Routing\Dispatcher::_invoke() - CORE\src\Routing\Dispatcher.php, line 120
Cake\Routing\Dispatcher::dispatch() - CORE\src\Routing\Dispatcher.php, line 87
require - ROOT\webroot\index.php, line 37
[main] - ROOT\index.php, line 16

And

Notice (8): Undefined index:  [CORE\src\ORM\Association\SelectableAssociationTrait.php, line 288]

Cake\ORM\Association\BelongsToMany::Cake\ORM\Association\{closure}() - CORE\src\ORM\Association\SelectableAssociationTrait.php, line 288
Cake\Database\Statement\CallbackStatement::fetch() - CORE\src\Database\Statement\CallbackStatement.php, line 58
Cake\ORM\ResultSet::_fetchResult() - CORE\src\ORM\ResultSet.php, line 477
Cake\ORM\ResultSet::valid() - CORE\src\ORM\ResultSet.php, line 269
include - APP/Template\Groups\index.ctp, line 10
Cake\View\View::_evaluate() - CORE\src\View\View.php, line 834
Cake\View\View::_render() - CORE\src\View\View.php, line 794
Cake\View\View::render() - CORE\src\View\View.php, line 465
Cake\Controller\Controller::render() - CORE\src\Controller\Controller.php, line 582
Cake\Routing\Dispatcher::_invoke() - CORE\src\Routing\Dispatcher.php, line 120
Cake\Routing\Dispatcher::dispatch() - CORE\src\Routing\Dispatcher.php, line 87
require - ROOT\webroot\index.php, line 37
[main] - ROOT\index.php, line 16

Cake still fetches the Groups table objects, but with no results from Servers table.

Note that i have prefix mn for tables for database organisation. I tried the associations without the prefixes with the same results. Also i'm using SQL Server database. My cake version is 3.0.10.

What could be the cause for this?

Answer 1

Judging from the errors and the code, this looks like your database tables have no primary key constraints set, which is necessary for CakePHP to find the column(s) that should act as the primary key, unless you explicitly specify which column(s) should be used.

Add the appropriate constraints for your id columns and it should work (don't forget to clear the model cache afterwards src/tmp/cache/models ).

Explicitly telling the table class which column(s) to use is possible using the Table::primaryKey() method.

// in your tables initialize() method
$this->primaryKey('id');

However, this should mostly really only be done additionally (this will avoid processing the schema), and not alternatively! Your tables really should have the PK constraints set unless you have a very good reason to not use them!

See also

• Cookbook > Database Access & ORM > Table Objects > Basic Usage
• API > \\Cake\\ORM\\Table::primaryKey()