多对多

可用方法

$user ->roles ()->save ()

$user ->roles ()->savemany  ()

save 和savemany 接收模型实例

$user ->roles ()->create()

$user ->roles ()->createmany()

接收数组，分别一维数组和二维数组

attach ()接收id 或者数组

detach ()接收id 或者数组

sync ()接收数组

toggle ()接收数组

更新belongto 关联

->associate($account)更新外键

取消dissociate($account)

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更新父级时间戳

  protected $touches = ['post'];