php 使用修改的主键更新条目时，Laravel 5.5 方法保存不存在

Laravel 5.5 Method save does not exist when updating entries with modified primary key

提问by Melaku Minas Kasaye

I am working with laravel 5.5 to update entries. The problem is after changing the primary key 'id', which is elequoent default pk to 'project_id'. adding an item works fine but updating an item is not working properly. Here is the error I am getting.

我正在使用 laravel 5.5 来更新条目。问题是在更改主键 'id' 之后，这是 elequoent 默认 pk 到 'project_id'。添加项目工作正常，但更新项目无法正常工作。这是我得到的错误。

Method save does not exist.

方法 save 不存在。

Here is my Model.

这是我的模型。

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Project extends Model
{
   protected $primaryKey = 'project_id';
    public function user()
    {
        return $this->belongsTo(User::class);
    }
    public function tasks()
    {
        return $this->hasMany(Task::class);
    }
}

Here is my controller function.

这是我的控制器功能。

public function editProject($id){

        $project = Project::where('project_id', $id)->firstOrFail();
        $data = ["project_info" => $project];
        return view('projects.edit')->with($data);
    }
    public function updateProject(Request $request){
        $data = $request->all();
        $validator = Validator::make($data, [
            'project_title' => 'required',
            'project_description' => 'required',
            'project_start_date' => 'required',
            'project_end_date' => 'required',
            'project_status' => 'required',
        ]);

        $response = [];

        if ($validator->fails()){
            $response["errors"] = [$validator->messages()->first()];
            $response["success"] = false;
            return json_encode($response);
        }

        else{
            $project = Project::where("project_id", $request->input('project_id'))->get();
            $project->project_title = $request->project_title;
            $project->user_id = Session::get('user_id');
            $project->project_description = $request->project_description;
            $project->project_start_date = $request->project_start_date;
            $project->project_end_date = $request->project_end_date;
            $project->project_status = $request->project_status;
            $project->save();
            return redirect('/listProjects');
        }
    }

回答by James

Using get()returns a collection. Despite the fact you are passing in a 'unique' ID, the project_id, it will still return a collection - the collection will simply have one element in it.

使用get()返回一个集合。尽管您传入了一个“唯一”ID，但project_id它仍然会返回一个集合 - 该集合中只会包含一个元素。

Subsequently, your code will not work as you have experienced, or at least not without a few changes to make $projectreference the first element in the collection.

随后，您的代码将无法像您所经历的那样工作，或者至少在没有一些更改以$project引用集合中的第一个元素的情况下。

It's a quick fix though, just change this:

不过，这是一个快速修复，只需更改此：

$project = Project::where("project_id", $request->input('project_id'))->get();

to this:

对此：

$project = Project::where("project_id", $request->input('project_id'))->first();

By using first(), eloquent will return the first element that matches the query and actually return the element (as opposed to a collection with one element) and so you can directly edit and save it.

通过使用first()，eloquent 将返回与查询匹配的第一个元素并实际返回该元素（而不是具有一个元素的集合），因此您可以直接编辑和保存它。

回答by Melaku Minas Kasaye

Here is the solution I found.

这是我找到的解决方案。

$project_id = $request->input('project_id');
$project = Project::find($project_id);
$project->save();

回答by Thiago Maciel

You can find it by id using

您可以使用 id 找到它

Project::find($id);

Project::find($id);

Or get the first element like James said:

或者像 James 说的那样获取第一个元素：

$project = Project::where("project_id", $request->input('project_id'))->first();