在对象输出上检索关系字段

Posted 2023-02-16

【中文标题】在对象输出上检索关系字段

【英文标题】：Retrieve relationship fields on object output

【发布时间】：2021-05-27 16:11:51

【问题描述】：

当将客户端对象输出到 JSON 时，我还需要包含区域字段，我该怎么做呢？我尝试过预先加载，但输出不包含字段。

模型

Client
public function Office()
    return $this->hasOne('App\Models|offices', 'ref_id', 'OfficeID')->where('DB', '=', $this->RemoteDatabase);


Office
public function region()
    return $this->belongsTo('App\Models\Regions', 'regions_id');

获取客户端的代码

$ModelOBJ = Clients::where('ClientCode', 'LIKE', $term)
    ->orderBy('ClientName', 'ASC');
if ((clone $ModelOBJ)->count() > 0)
    $ClientData = $ModelOBJ->with('Office.Region:HRName')->get();
    return response()->json(['code' => '200', 'Client' => $ClientData, 'querieis'=> \DB::getQueryLog()]);

这将返回以下内容

    code    "200"
    Client  [ …, … ]
    querieis    [ …, …, … ]
    0   Object  query: "select count(*) as aggregate from [Clients] where [ClientCode] LIKE ?", time: 56.64, bindings: […] 
    query   "select count(*) as aggregate from [Clients] where [ClientCode] LIKE ?"
    bindings    [ "test" ]
    0   "test"
    time    56.64
    1   Object  query: "select * from [Clients] where [ClientCode] LIKE ? order by [ClientName] asc", time: 59.12, bindings: […] 
    query   "select * from [Clients] where [ClientCode] LIKE ? order by [ClientName] asc"
    bindings    [ "test" ]
    0   "test"
    time    59.12
    2   Object  query: "select * from [Offices] where [Active] = ? and [DB] is null and [Offices].[ref_id] in (?, ?)", time: 2.55, bindings: […] 
    query   "select * from [Offices] where [Active] = ? and [DB] is null and [Offices].[ref_id] in (?, ?)"
    bindings    [ "Y", "1", "5" ]
    time    2.55

【参考方案1】：

在预先加载中加载特定字段时，您还应该选择用于映射相关记录的记录标识符。所以在你的情况下(belongsTo)它的idRegion的主键

$ModelOBJ->with('Office.Region:id,HRName')->get();

See Eager Loading Specific Columns

使用此功能时，您应该始终在要检索的列列表中包含 id 列和任何相关的外键列。