Laravel 模型中的 delete() 函数问题

Question

我想使用 laravel 模型中的删除函数从类别中删除一条记录，但这个函数让我成为一个奇怪的查询，没有意义。因此，我得到了一个错误（sql 约束失败）。 Laravel 执行以下奇怪的查询：从

t_category

删除，其中

t_category

.

catLeft

> 505 和

t_category

.

catRight

< 518 order by

t_category

.

catLeft

asc

为什么 laravel 不搜索 id 并删除找到的第一条记录？

我的控制器：删除功能

/**
   * Remove the category
   * @param  Request $request
   * @param  String  $no      category's no
   * @return \Illuminate\Http\RedirectResponse Redirect to the list of category
   */
  public function remove(Request $request, $no){
    // Get the category
    $category = Category::findByNo($no);

    if ($category == null)
      return redirect('/gest/categories');

    if ($category->isRoot())
      return redirect('/gest/categories');

    $parentID  = Category::where('catParentId', $category->idCategory)->get();

    try {

      if(empty($parentID[0]["catNo"]))
      {
        $category->delete();
        
        $request->session()->flash('message', ['result' => true,'title' => Lang::get('gest.deleteSucces.title'), 'msg' => Lang::get('gest.deleteSucces.msg', array('model' => $category->catNo.' - '.$category->catName))]);
      }
      else
      {

        $request->session()->flash('message', ['result' => false,'title' => Lang::get('gest.deleteCategoryParent.title'), 'msg' =>  Lang::get('gest.deleteCategoryParent.msg', array('category' => $category->catNo.' - '.$category->catName))]);
        return redirect('/gest/categories');
      }

    }
    catch (\Illuminate\Database\QueryException $e) {
      if ($e->errorInfo[1] == "1451")// SQL code 1451 = Constraint fail
          $request->session()->flash('message', ['result' => false,'title' => Lang::get('gest.deleteCategoryEchecContraintFail.title'), 'msg' =>  Lang::get('gest.deleteCategoryEchecContraintFail.msg', array('category' => $category->catNo.' - '.$category->catName))]);
      else
        $request->session()->flash('message', ['result' => false,'title' =>Lang::get('gest.deleteModelEchecUnknownError.title'), 'msg' =>  Lang::get('gest.deleteModelEchecUnknownError.msg', array('model' => $category->catNo.' - '.$category->catName))]);
    }
    return redirect()->back();
  }

类别型号：

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use App\Exceptions\InvalidArgumentExceptionClass;
use App\Traits\Uuids;
use Baum\NestedSet\Node;

class Category extends Model {
  use Node;
  use Uuids;

  /**
   * The attributes that are mass assignable.
   *
   * [See laravel seeding documentation](https://laravel.com/docs/5.7/eloquent)
   * @var array
   */
  protected $fillable = ['catNo', 'catName'];

  /**
   * The attributes that aren't mass assignable.
   * @var array
   */
  protected $guarded = ['idCategory','catParentId','catLeft','catRight','catDepth'];

  /**
   * The attributes that should be hidden for arrays.
   * @var array
   */
  protected $hidden = ['idCategory','catParentId'];

  /**
   * The table associated with the model.
   * @var String
   */
  protected $table = 't_category';

  /**
   * The "type" of the primary key ID.
   *
   * @var string
   */
  protected $keyType = 'string';

  /**
   * The primary key for the model.
   * @var String
   */
  protected $primaryKey = "idCategory";

  /**
   * Indicates if the IDs are auto-incrementing.
   * @var boolean
   */
  public $incrementing = false;

  /**
   * Indicates if the timestamps crated_at and updated_at are saved.
   * @var boolean
   */
  public $timestamps = false;

  // 'parent_id' column name
  protected $parentColumnName = 'catParentId';

  // 'lft' column name
  protected $leftColumnName = 'catLeft';

  // 'rgt' column name
  protected $rightColumnName = 'catRight';

  // 'depth' column name
  protected $depthColumnName = 'catDepth';


  /**
   * Get the kits that belong to the category
   *
   * @return array Kit
   */
  public function kits() {
      return $this->hasMany(Kit::class,'fkCategory')
        ->orderBy('kitNo','asc');
  }

  /**
   * Get the Additional Items that belong to the category
   *
   * @return array AddItem
   */
  public function addItems() {
      return $this->hasMany(AddItem::class,'fkCategory')
        ->orderBy('adiName','asc');
  }

  /**
   * Create an Category
   *
   * @param array $attributes
   *
   * @return \App\Models\Category
   *
   * @throws \App\Exceptions\InvalidArgumentExceptionClass
   */
  public static function create(array $attributes = []) {
      // Check if not duplicate No
      if (static::where('catNo', $attributes['catNo'])->first()) {
        throw InvalidArgumentExceptionClass::modelWithNoAlreadyExist(Category::class,$attributes['catNo']);
      }

      return static::query()->create($attributes);
  }

  /**
   * Find a Category by its id
   *
   * @param string $idCategory
   *
   * @return \App\Models\Category|null
   */
  public static function findById(string $idCategory) {
      $category = static::where('idCategory', $idCategory)->first();

      if (! $category) {
          return null;
      }

      return $category;
  }

  /**
   * Find a Category by its No
   *
   * @param string $catNo
   *
   * @return \App\Models\Category|null
   */
  public static function findByNo(string $catNo) {
      $category = static::where('catNo', $catNo)->first();

      if (! $category) {
          return null;
      }

      return $category;
  }
}

我尝试使用销毁函数在函数中传递类别的 id，但出现同样的错误

Answer 1

查询的原因是您的模型正在使用

Baum\NestedSet\Node

特征。

鉴于删除单个节点可能需要删除或相关节点，嵌套集会构建适合您要删除的实例的查询。

要获得更简单的

DELETE FROM table WHERE id = x

查询，您需要删除

Node

特征，但这会破坏您想要保留的其他功能。

但是，我不认为你的问题是删除查询本身。你说：

所以，我得到了一个错误（sql 约束失败）作为结果

这可能是外键约束错误，这意味着您的其他模型之一依赖于您的类别模型。 如果您检查迁移，您可能会看到类似的内容

$table->foreign('category_id')->references('id')->on('categories');

或者

$table->foreignId('category_id')->constrained();

这意味着在删除类别之前，您需要删除附加到该类别的所有模型。 或者您可以定义

ON DELETE

行为，例如

$table->foreignId('category_id')
      ->constrained()
      ->onDelete('cascade');

这意味着当您删除 Category 实例时，所有相关实例也将被删除。

另一个选项是删除数据库中的外键约束，方法是编辑迁移并全新迁移数据库，或者创建迁移来更改受约束的表。

这里的文档应该有帮助