Thinkphp the parent of a record in the correlation model (non-query children)

Data Sheet

ID cat_name cat_pid

76 mobile phone, digital 0

84 Mobile Phone Accessories 76

86 Bluetooth Headset 84

Affiliation : Bluetooth headset = (previous level) mobile phone accessories = (previous level) mobile phone, digital ( top -level)

Correlation model

Namespace Admin\model;use think\model\relationmodel;class Categorymodel extends relationmodel{protected $_link = array (' Category ' = = Array (///table name ' Mapping_type ' =>self::belongs_to,   //key.) This is the query parent  and the Has_m Any is the query child ' mapping_name ' = ' _parent ',//Custom ' mapping_order ' = ' cat_sort ', ' par Ent_key ' = ' cat_pid ',//key. The name of the field associated with the parent);

Code in the controller:

Public Function Search () {
    $category = D (' category ');  The D method is used. To use the correlation model

$id =;   At this time 86 this ID is the lowest level in the data table. $this->id = $category->where (' id= '. $id)->order (' Cat_sort ')->relation (True)->select ();   This time the query is 86 of the previous level. That is, the id=84, mobile phone accessories   $lastPid = $category,relationget(true);   If you want to make an association query based on the completed query, use the Relationget () method
Dump ($LASTPID);
The $lastpid is the topmost data (id=76, mobile, digital). (only if the data table is a three-tier structure.) If it is a two-tier structure, then the $this->id is already at the top level, and you do not need to use the Relationget () method)
  If you do this again, you can query to a higher parent, provided the data table is a four-tier structure, and so on.
$lastLastPid = $category->relationget (true);  
}

Thinkphp the parent of a record in the correlation model (non-query children)