php - Laravel : Check if record exists Before Insertion

Question

我有两张 table : assignments 表(列 assignment_id 、 Staff Name 、 asset_id 、 department 、 date 、 status )和 assets 表(列 asset_id 、 tag_name 、 serial_number 、 model_number 、 color )。 Assets 表列与 链接作业 table 。我想插入到分配表中，但在插入之前，我想检查 asset_id 已存在于分配表中，如果是 status = 'Active' 那么插入应该抛出错误/不应该发生。

作业 Controller

class AssignmentController extends Controller
{

public function assignment(){
    $assignments = Assignment::all();
    return view('assignment/index', ['assignments' => $assignments]);
}   

  public function add(Request $request){

    $this->validate($request, [
        'assignment_id' => '',
        'staff_name' => 'required',
        'asset_id' => 'required',
        'department' => 'required',
        'date' => 'required',
        'status' => 'required'
    ]);
    $assignments =  new Assignment;
    $assignments  ->assignment_id = $request->input('assignment_id');
    $assignments  ->staff_id  = $request->input('staff_id');
    $assignments  ->asset_id = $request->input('asset_id');
    $assignments  ->department_id = $request->input('department_id');
    $assignments  ->date  = $request->input('date');
    $assignments  ->status = $request->input('status');

$count = Assignment::where('status', '=' ,'Active' )->
    where('asset_id', '=' ,$assignments->asset_id)->
    count();
    if($count) {
        abort(405, 'Trying to assign an already assigned asset');
    }

    $assignments  ->save();
    return redirect('/assignment/index') ->with('info', 'New Assignment Saved Successfully!');
}

Assginment.php

class Assignment extends Model
{
    protected $primaryKey = 'assignment_id';    

    public function asset()
    {
        return $this->belongsTo('App\Asset', 'asset_id');
    }
}

以下变量和 中的 if 语句AssignmentsController 总是在 中抛出错误if statement 无论它是否正确并且插入不会发生，但是当整个语句被清除时，插入就会发生。

$count = Assignment::where('status', '=' ,'Active' )->
        where('asset_id', '=' ,$assignments->asset_id)->
        count();
        if($count) {
            abort(405, 'Trying to assign an already assigned asset');
        } 

所以我想要一种方法来检查要插入的记录是否已经存在，条件好像 asset_id 存在然后检查它的 status 如果它是 ='Active' 然后抛出一个错误，但如果不是，则插入发生。如果你明白，请帮助。提前致谢。

Answer 1

你可以这样做:

public function add(Request $request){
    $this->validate($request, [
        'assignment_id' => '',
        'staff_name' => 'required',
        'asset_id' => 'required',
        'department' => 'required',
        'date' => 'required',
        'status' => 'required'
    ]);
    $assignment = Assignment::firstOrNew([ 
           "status" => "Active", 
           "asset_id" => $assignments->asset_id
    ], $request->all()); 
    abort_if($assignment->exists(), 405, 'Trying to assign an already assigned asset'); 
    $assignment->save();
    return redirect('/assignment/index')
          ->with('info', 'New Assignment Saved Successfully!');
}