检索数据时"无法将值转换为字符串"(belongsToMany关系)

Question

我正在使用CakePHP 3.3.6和MySQL 5.7.13.

我的数据库(以及其他)中有这三个表:集合,标签和连接表collections_tags.

集合表

CREATE TABLE IF NOT EXISTS `database`.`collections` (
  `id` INT UNSIGNED NOT NULL AUTO_INCREMENT,
  `name` VARCHAR(45) NOT NULL,
  `event_date` DATE NOT NULL,
  `url_slug` VARCHAR(45) NOT NULL,
  `status` TINYINT(1) NOT NULL DEFAULT 0,
  `user_id` INT UNSIGNED NOT NULL,
  `created` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `modified` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`, `user_id`),
  INDEX `fk_collections_users1_idx` (`user_id` ASC),
  CONSTRAINT `fk_collections_users1`
    FOREIGN KEY (`user_id`)
    REFERENCES `database`.`users` (`id`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION,
ENGINE = InnoDB

标签表

CREATE TABLE IF NOT EXISTS `database`.`tags` (
  `id` INT UNSIGNED NOT NULL AUTO_INCREMENT,
  `name` VARCHAR(45) NOT NULL,
  `created` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `modified` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`))
ENGINE = InnoDB

collections_tags表

CREATE TABLE IF NOT EXISTS `database`.`collections_tags` (
  `id` INT NOT NULL AUTO_INCREMENT,
  `collection_id` INT UNSIGNED NOT NULL,
  `tag_id` INT UNSIGNED NOT NULL,
  PRIMARY KEY (`id`, `collection_id`, `tag_id`),
  INDEX `fk_collections_has_tags_tags1_idx` (`tag_id` ASC),
  INDEX `fk_collections_has_tags_collections1_idx` (`collection_id` ASC),
  CONSTRAINT `fk_collections_has_tags_collections1`
    FOREIGN KEY (`collection_id`)
    REFERENCES `database`.`collections` (`id`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION,
  CONSTRAINT `fk_collections_has_tags_tags1`
    FOREIGN KEY (`tag_id`)
    REFERENCES `database`.`tags` (`id`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB

在我的Table\CollectionsTable.php中:

public function initialize(array $config)
{
    # A collection hasMany Sets
    $this->hasMany('Sets', [
        'dependent' => True,
    ]);

    # A Collection belongsTo a User
    $this->belongsTo('Users');

    # A Collection belongsToMany Tags
    $this->belongsToMany('Tags');
}

在我的表\ TagsTable.php中:

public function initialize(array $config)
{
    # A Tag belongsToMany Collections
    $this->belongsToMany('Collections');
}

我可以获得所有收藏品或所有标签.有用.但是,如果我尝试使用相关标签获取所有集合,则会出现此错误:

在我的Collections控制器中有此错误时会发生此错误:

class CollectionsController extends AppController
{
    public function index()
    {
        $this->set('collections', $this->Collections->find('all', ['contain' => ['Tags']]));
    }
}

这在我的Template\Collections\index.ctp中:

<h1>Hi, this is the Collection > Index page.</h1>

<?php foreach ($collections as $collection): ?>
<p>test</p>
<?php endforeach; ?>

我不知道为什么......我尝试创建一个Table\CollectionsTagsTable.php文件,但它并没有什么区别.

谢谢你的帮助

编辑:我尝试通过TIMESTAMP更改DATETIME字段,通过INT更改TINYINT,它没有改变任何东西.

Answer 1

使用类似的设置在本地测试它.看起来像"user_id"集合表中的主键索引会导致此处出现问题.删除它,问题就消失了.

我实际上并不了解复合键及其在CakePHP3中的用法,所以也许有经验丰富的人可以告诉我,为什么这会失败.