我有一个BlogPost控制器，该控制器具有一个用户表单，该表单通过create（）方法接收用户的输入。然后，该表单将重定向到同一控制器上的store方法。我面临的问题是多对多关系。 BlogPost模型与BlogTag模型具有多对多关系。我正在通过复选框从用户那里获取输入。用户可以选择与单个标签关联的多个单选按钮（下面已张贴了表单代码）。一切似乎都工作正常，但是当我尝试将所有标签ID附加到store（）方法中的post实例上时。我收到如下所示的错误。我已经浏览了互联网上所有可用的解决方案，但似乎没有任何解决方案。该存储方法也已发布在下面。
Connection.php 761行中的QueryException：SQLSTATE [23000]：完整性
约束违反：1452无法添加或更新子行：外部
键约束失败（erp_system_solution。posts_tags，CONSTRAINT
posts_tags_ref_tag_id_foreign外键（ref_tag_id）参考
blog_tags（tag_id）在更新级联上删除级联（SQL：
插入posts_tags（ref_post_id，ref_tag_id）值（2，34），
（7，34），（8，34），（15，34））
张贴BlogPost的表格
{{Form::open(array(
'action' => 'Blog\BlogPostController@store',
'class' => 'form-horizontal',
'method' => 'POST',
))}}
{{ Form::hidden('user_id', Auth::user()->user_id) }}
<div class="form-group">
{{ Form::label("post_title", "Post Title", array("class" => "col-sm-2 control-label")) }}
{{ Form::text ("post_title", "", array("class" => "col-sm-6")) }}
</div>
<div class="form-group">
{{ Form::label("post_body", "Post Body", array("class" => "col-sm-2 control-label")) }}
{{ Form::textarea("post_body", "", array("class" => "col-sm-6 col-sm-offset-2 top-info-panels", "rows" => "16", "columns" => "2")) }}
</div>
<div class="form-group">
{{ Form::label("published", "Publish Blog Post", array("class" => "col-sm-2 control-label")) }}
{{ Form::radio("published", "Yes", true) }} Yes
{{ Form::radio("published", "No") }} No
</div>
<div class="form-group">
{{ Form::label("category_id", "Choose a Category", array("class" => "col-sm-2 control-label")) }}
{{ Form::select("category_id", $categories, '-----Choose Any One-----') }}
</div>
<div class="form-group">
{{ Form::label("tag_id", "Choose Appropriate Tags", array("class" => "col-sm-2 control-label")) }}
<div class="col-sm-offset-2">
@for($i=1; $i<count($tags)+1; $i++)
{{ Form::checkbox("tag_id[]", $i), array("class" => "col-sm-offset-2 col-sm-10") }} {{ $tags[$i] }}
@endfor
</div>
</div>
<div class="form-group">
<div class="col-sm-offset-2 col-sm-10">
{{Form::submit('Create Post', array("class" => "btn btn-warning"))}}
</div>
</div>
{{Form::close()}}
BlogPostModel
<?php
namespace App;
use App\PostsTagsPivot as Pivot;
use App\BlogCategory;
use App\BlogTag;
use App\Comment;
use App\RegisteredUser;
use Illuminate\Database\Eloquent\Model;
class BlogPost extends Model
{
public $timestamps = true;
protected $table = 'blog_posts';
protected $primaryKey = 'post_id';
protected $fillable = ['post_title', 'post_body', 'published', 'registered'];
public function post_category() {
return $this->belongsTo(BlogCategory::class, 'category_id');
}
public function posts_with_tags() {
return $this->belongsToMany(BlogTag::class, 'posts_tags', 'ref_tag_id', 'ref_post_id');
}
public function comments() {
return $this->hasMany(Comment::class, 'comment_id');
}
public function posts_author() {
return $this->belongsTo(RegisteredUser::class, 'user_id');
}
}
BlogPostController
public function store(Request $r) {
$u_id = $this->user::find((int)$r->input('user_id'));
$cat_id = $this->category::find((int)$r->input('category_id'));
$tag_id = $r->input('tag_id');
$role = $this->user::find((int)$r->input('user_id'))->has_role($u_id);
$registered = ($role == 'super_admin') ? true : false;
$published = ($r->input('published') == 'Yes') ? true : false;
$create_post = $this->blog_posts::create(['post_title' => $r->input('post_title'), 'post_body' => $r->input('post_body'), 'published' => $published, 'registered' => $registered]);
$create_post->save();
$create_post->posts_with_tags()->attach($tag_id);
$create_post->save();
$create_post->posts_author()->associate($u_id);
$create_post->save();
$create_post->post_category()->associate($cat_id);
if($create_post->save()) return redirect()->route('blog_post.create')->with('post_saved', 'Your post has been saved');
else return redirect()->route('blog_post.create')->with('post_not_saved', 'Something went wrong');
}
BlogTagModel
<?php
namespace App;
use App\BlogPost;
use Illuminate\Database\Eloquent\Model;
class BlogTag extends Model
{
public $timestamps = true;
protected $table = 'blog_tags';
protected $primaryKey = 'tag_id';
protected $fillable = ['tag_name', 'post_id', 'tag_id'];
public function tags_on_posts() {
return $this->belongsToMany(BlogPost::class, 'posts_tags', 'ref_tag_id', 'ref_post_id');
}
}
迁移数据透视表以将BlogPost与BlogTag连接
public function up()
{
Schema::create('posts_tags', function ($table) {
$table->integer('ref_tag_id')->unsigned()->index();
$table->foreign('ref_tag_id')->references('tag_id')->on('blog_tags')->onDelete('cascade')->onUpdate('cascade');
$table->integer('ref_post_id')->unsigned()->index();
$table->foreign('ref_post_id')->references('post_id')->on('blog_posts')->onDelete('cascade')->onUpdate('cascade');
});
}
最佳答案
好吧，我知道了。解决方案是更改posts_with_tags（）操作/方法中的顺序
它是：
public function posts_with_tags() {
return $this->belongsToMany(BlogTag::class, 'posts_tags', 'ref_tag_id', 'ref_post_id');
}
它应该是：
public function posts_with_tags() {
return $this->belongsToMany(BlogTag::class, 'posts_tags', 'ref_post_id', 'ref_tag_id');
}
关于php - SQLSTATE [23000]违反完整性约束:laravel 5.3中多对多关系中的1452，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/40063476/