laravel - 为什么模型看不到第二个外键？

Question

我有下一个代码：

$project = Project::findOrFail($projectId);
$experiments = $project->experiments;

dd($experiments->find($experimentId)->statistic);

为什么Statistic模型看不到project_id外键？

只有此代码有效：

$experiments->find($experimentId)->statistic()->where('project_id', $project->id)->first()

项目 <-> 实验（多对多）；实验 -> 统计（一对一）

标签： laraveleloquent

Answer 1

尝试急切加载实验和统计

$project = Project::with('experiment.statistic')->findOrFail($projectId);
$experiments = $project->experiments;

dd($experiments->find($experimentId)->statistic);