I've got a BlogPost Controller which has a user form that takes inputs from the user through the create() method. Then that form redirects to the store method on the same controller. The problem I'm facing is with the many-to-many relationship. BlogPost model has a many-to-many relationship with the BlogTag model. I'm taking input from a user through checkboxes. The user can choose multiple radio buttons associated with individual tags (form code has been posted below). Everything seems to work fine, but when I'm trying to attach all the tag ids to the post instance in my store() method. I get the error that is shown below. I've looked through all the available solutions on the internet but nothing seems to work for my case. The store method has also been posted below.
QueryException in Connection.php line 761: SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (
erp_system_solution.posts_tags, CONSTRAINTposts_tags_ref_tag_id_foreignFOREIGN KEY (ref_tag_id) REFERENCESblog_tags(tag_id) ON DELETE CASCADE ON UPDATE CASCADE) (SQL: insert intoposts_tags(ref_post_id,ref_tag_id) values (2, 34), (7, 34), (8, 34), (15, 34))
Form for posting a BlogPost
{{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 $this->belongsToMany(BlogPost::class, 'posts_tags', 'ref_tag_id', 'ref_post_id');
}
}
Migration for a pivot table joining BlogPost with BlogTag
public function up()
{
Schema::create('posts_tags', function ($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');
});
}
Well, I figured it out. The solution is to change the ordering in posts_with_tags() action/method
It was:
public function posts_with_tags() {
return $this->belongsToMany(BlogTag::class, 'posts_tags', 'ref_tag_id', 'ref_post_id');
}
It should be:
public function posts_with_tags() {
return $this->belongsToMany(BlogTag::class, 'posts_tags', 'ref_post_id', 'ref_tag_id');
}