带有Laravel的数据透视表的问题

Question

我在Laravel中创建数据透视表时遇到问题。这是我第一次使用它，并且在Internet上搜索后，我无法设法解决问题。

SQLSTATE[42S22]: Column not found: 1054 Unknown column 'champions_teams.teams_id' in 'field list' (SQL: select `champions`.*, `champions_teams`.`teams_id` as `pivot_teams_id`, `champions_teams`.`champions_id` as `pivot_champions_id`, `champions_teams`.`champion_id` as `pivot_champion_id` from `champions` inner join `champions_teams` on `champions`.`id` = `champions_teams`.`champions_id` where `champions_teams`.`teams_id` = 1) (View: C:\laragon\www\proyecto-web\resources\views\teams\teamIndex.blade.php)

以下，是我通过数据透视表迁移创建类“冠军”和“团队”的方式。

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\softDeletes;

class Teams extends Model
{
    use SoftDeletes;
    protected $table = 'teams';
    protected $fillable = ['user_id','name','rank','region'];

    public function user(){
        return $this->belongsTo(User::class);
    }

    public function champions(){
        return $this->belongsToMany(Champions::class)->withPivot('champion_id');
    }

    public function files(){
        return $this->morphMany(File::class, 'model');
    }

    public function setNameAttribute($value){
        $this->attributes['name'] = strtoupper($value);
    }

    public function getTeamsNameAttribute(){
        return $this->name;
    }
}

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Champions extends Model
{
    protected $table = 'champions';
    protected $fillable = ['name','health_points','type','role'];

    public function teams(){
        return $this->belongsToMany(Teams::class)->withPivot('team_id');;
    }

    public function items(){
        return $this->hasMany(Items::class, 'champion_id');
    }

}

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class PivotTables extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {

        Schema::create('champions_teams', function(Blueprint $table){
            $table->unsignedBigInteger('champion_id');
            $table->unsignedBigInteger('team_id');

            $table->foreign('champion_id')
                ->references('id')
                ->on('champions')
                ->onDelete('cascade');

            $table->foreign('team_id')
                ->references('id')
                ->on('teams')
                ->onDelete('cascade');
        });

    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        //
    }
}

感谢您的帮助！您也可以在此处访问整个代码：https://github.com/ValentinDelpy/proyecto-web

Answer 1

似乎您与团队和团队发生冲突。

您的模型名为Teams（应为Team）。

结帐如何正确地建立多对多关系：

Laravel docs

Answer 2

[Laravel可能是从Model名称生成ID的，所以如果Project是全新的，只需对其进行更改，否则，您必须在belogsToMany函数中声明外键名称（检查https://laravel.com/api/6.x/Illuminate/Database/Eloquent/Concerns/HasRelationships.html#method_belongsToMany）。

还请记住，witPivot功能是让Laravel知道其他字段的存在，而不仅仅是两个外键，而不是它们自己的外键（检查https://laravel.com/api/6.x/Illuminate/Database/Eloquent/Relations/BelongsToMany.html#method_withPivot）

Answer 3

Many to Many由于您未遵循Laravel期望的名称约定，因此应通过将附加参数传递给belongsToMany方法来自定义联接表的名称，即表上键的列名称。第三个参数是您要在其上定义关系的模型的外键名称，而第四个参数是您要加入的模型的外键名称：

class Champions extends Model
{

    public function teams(){
        return $this->belongsToMany(Teams::class, 'champions_teams', 'team_id', 'champion_id');
    }

}

class Teams extends Model
{
    public function champions(){
        return $this->belongsToMany(Champions::class, 'champions_teams', 'champion_id', 'team_id');
    }

}