legend3---lavarel多对多模型操作实例

legend3---lavarel多对多模型操作实例

一、总结

一句话总结：

在多对多模型中，增加关系表的数据 需要 弄一个和关系表一对多的模型关系

1、在lavarel关系模型中，课程和标签表是多对多，那么我如何增加课程标签联合表的数据？

定义一个一对多的模型，因为课程和标签表是多对多，那么课程和课程标签联合表是一对多

//与课程标签联合表的一对多关系
public function hasManyLessonTags(){
  return $this->hasMany(\App\Model\Admin\TagAndLesson::class,'tl_l_id','l_id');
}

//2、插入标签课程数据--关系表
$tags=$request['tags'];
foreach ($tags as $tag){
    $tag_lesson=[];
    $tag_lesson['tl_t_id']=$tag;
    //$tag_lesson['tl_l_id']=$lesson['l_id'];
    //TagAndLesson::create($tag_lesson);
    //dd($tag_lesson);
    $lesson->hasManyLessonTags()->create($tag_lesson);

}

2、在lavarel关系模型中，定义模型关系的第一个参数是什么意思：例如$this->hasMany(Video::class,'v_l_id','l_id');？

关联的模型，也就是【最终要获取数据的表模型】，这里是哪个模型就表示要操作哪个表

3、在lavarel关系模型中，课程和标签表是多对多，我在定义好了多对多的模型关系，我能否用这个模型关系增加课程标签联合表的数据？

不能，因为模型关系的第一个参数是最终要操作数据的表模型

二、lavarel多对多模型操作实例

1、关系和数据表结构

课程和标签表是多对多

课程表：lessons

CREATE TABLE `lessons`  (
  `l_id` int(10) UNSIGNED NOT NULL AUTO_INCREMENT,
  `l_title` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
  `l_introduce` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
  `l_preview` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
  `l_is_commend` tinyint(4) NOT NULL,
  `l_is_hot` tinyint(4) NOT NULL,
  `l_click` int(11) NOT NULL DEFAULT 0 COMMENT '点击数/浏览数',
  `l_like` int(11) NOT NULL DEFAULT 0 COMMENT '点赞数',
  `l_comment_num` int(11) NOT NULL DEFAULT 0 COMMENT '评论数',
  `created_at` timestamp(0) NULL DEFAULT NULL,
  `updated_at` timestamp(0) NULL DEFAULT NULL,
  PRIMARY KEY (`l_id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 27 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;

标签表：tags

CREATE TABLE `tags`  (
  `t_id` int(10) UNSIGNED NOT NULL AUTO_INCREMENT,
  `t_name` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
  `created_at` timestamp(0) NULL DEFAULT NULL,
  `updated_at` timestamp(0) NULL DEFAULT NULL,
  PRIMARY KEY (`t_id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 4 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;

课程标签表：tag_and_lessons

CREATE TABLE `tag_and_lessons`  (
  `tl_id` int(10) UNSIGNED NOT NULL AUTO_INCREMENT,
  `tl_t_id` int(11) NOT NULL COMMENT '标签id',
  `tl_l_id` int(11) NOT NULL COMMENT '课程id',
  `created_at` timestamp(0) NULL DEFAULT NULL,
  `updated_at` timestamp(0) NULL DEFAULT NULL,
  PRIMARY KEY (`tl_id`) USING BTREE,
  INDEX `tag_and_lessons_tl_t_id_index`(`tl_t_id`) USING BTREE,
  INDEX `tag_and_lessons_tl_l_id_index`(`tl_l_id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 15 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;

2、模型代码

app/Model/Lesson.php

 <?php

 namespace App\Model;

 use Illuminate\Database\Eloquent\Model;

 class Lesson extends Model
 {
     protected $primaryKey='l_id';
     /**
      * 与视频表模型的一对多关联
      * @return \Illuminate\Database\Eloquent\Relations\HasMany
      */
     public function videos(){
         return $this->hasMany(Video::class,'v_l_id','l_id');
     }

     //与标签的多对多关系
     public function hasManyTags(){
         return $this->belongsToMany('App\Model\Tag','tag_and_lessons','tl_l_id','tl_t_id');
     }

     //与课程标签联合表的一对多关系
     public function hasManyLessonTags(){
         return $this->hasMany(\App\Model\Admin\TagAndLesson::class,'tl_l_id','l_id');
     }
 }

app/Model/Tag.php

<?php

namespace App\Model;

use Illuminate\Database\Eloquent\Model;

class Tag extends Model
{
    //$guarded表示不允许批量填充的字段
    protected $primaryKey='t_id';
    protected $guarded=[];

}

app/Model/Admin/TagAndLesson.php

<?php

namespace App\Model\Admin;

use Illuminate\Database\Eloquent\Model;

class TagAndLesson extends Model
{
    //
    protected $primaryKey='tl_id';
    protected $guarded=[];
}

3、控制器中使用的代码

app/Http/Controllers/Admin/LessonController.php

     public function store(Request $request,Lesson $lesson)
     {
         DB::transaction(function () use ($request,$lesson) {
             //dd($request->toArray());
             $lesson['l_title']=$request['l_title'];
             $lesson['l_introduce']=$request['l_introduce'];
             $lesson['l_preview']=$request['l_preview'];
             $lesson['l_is_commend']=$request['l_is_commend'];
             $lesson['l_is_hot']=$request['l_is_hot'];
             $lesson['l_click']=$request['l_click'];
             $lesson->save();
             //dd($lesson['l_id']);
             //dd($lesson->toArray());

             //2、插入标签课程数据--关系表
             $tags=$request['tags'];
             foreach ($tags as $tag){
                 $tag_lesson=[];
                 $tag_lesson['tl_t_id']=$tag;
                 //$tag_lesson['tl_l_id']=$lesson['l_id'];
                 //TagAndLesson::create($tag_lesson);
                 //dd($tag_lesson);
                 $lesson->hasManyLessonTags()->create($tag_lesson);

             }

             //videos数据过来的时候是json数据,true表示转成数组而非对象
             $videos=json_decode($request['videos'],true);
             //dd($videos);
             foreach ($videos as $video){
                 unset($video['v_id']);
                 $lesson->videos()->create($video);
 //            $lesson->videos()->create([
 //                'title'=>$video['title'],
 //                'path'=>$video['path'],
 //            ]);
             }
         });

         return redirect('/admin/lesson');

     }