我有以下情况:作品有一个Image属于ImageGroup.
如果我这样做:
$works = $this->Work->find('all', array(
'contain' => array(
'PreviewImage' => array(
'fields' => array('PreviewImage.id', 'PreviewImage.filename', 'PreviewImage.alt'),
'ImageGroup' => array(
'fields' => array('ImageGroup.id')
)
)
)
));
我会得到这个:
array(
(int) 0 => array(
'Work' => array(
'id' => '1',
'title_us' => 'Work Title',
'title_de' => 'Arbeit Titel',
'alias' => 'work-title',
'pdf_id' => '1',
'date' => '2013-10-08 10:36:00',
'title_graphic_us_id' => '1',
'title_graphic_de_id' => '2',
'body_us' => 'English Content',
'body_de' => 'Deutscher Inhalt',
'preview_image_id' => '3',
'preview_us' => 'English Preview Text',
'preview_de' => 'Deutscher Vorschau Text',
'work_layout_id' => '2',
'state_id' => '1'
),
'PreviewImage' => array(
'id' => '3',
'filename' => 'preview_image.png',
'alt' => 'Preview Image',
'image_group_id' => '2',
'ImageGroup' => array(
'id' => '2'
)
)
)
)
但是如果我想通过以下方法减少工作领域:
$works = $this->Work->find('all', array(
'fields' => array(
'Work.id'
),
'contain' => array(
'PreviewImage' => array(
'fields' => array('PreviewImage.id', 'PreviewImage.filename', 'PreviewImage.alt'),
'ImageGroup' => array(
'fields' => array('ImageGroup.id')
)
)
)
));
我突然不再在PreviewImage中获得ImageGroup,请看这里:
array(
(int) 0 => array(
'Work' => array(
'id' => '1'
),
'PreviewImage' => array(
'id' => '3',
'filename' => 'preview_image.png',
'alt' => 'Preview Image',
'image_group_id' => '2'
)
)
)
我不明白为什么,你有什么想法吗?
解决方法:
我不是100%确定这是否是预期的行为,但您必须在字段配置中包含PreviewImage外键字段才能使其正常工作:
$works = $this->Work->find('all', array(
'fields' => array(
'Work.id',
'Work.preview_image_id'
),
'contain' => array(
...
)
));
文档提到确保在使用包含的fields选项时包含所有必需的外键:
When using ‘fields’ and ‘contain’ options – be careful to include all foreign keys that your query directly or indirectly requires.
http://book.cakephp.org/2.0/en/core-libraries/behaviors/containable.html