Wrong table when updating "Belongs To" relationships in Laravel - php

Question

Here I'm trying to save article's category with given id which exists in categories table,I have set the relationships but when trying to save, Laravel tries to insert new row in articles table not in the pivot table .
Here is the error:
*Unknown column 'category_id' in 'field list' (SQL: update `articles` set `category_id` = 1, `updated_at` = 2015-11-16 13:15:32 where `id` = 53)*
And these are relations and pivot table
class Article extends Model implements SluggableInterface
{
public function category()
{
return $this->belongsTo('App\Category');
}
}
class Category extends Model implements SluggableInterface
{
public function articles()
{
return $this->hasMany('App\Article','article_category');
}
}
//pivot table
Schema::create('article_category',function(Blueprint $table){
$table->integer('article_id')->unsigned()->index();
$table->foreign('article_id')->references('id')->on('articles')->onDelete('cascade');
$table->integer('category_id')->unsigned()->index();
$table->foreign('category_id')->references('id')->on('categories')->onDelete('cascade');
$table->timestamps();
});
And here is my save function
public function store(ArticleRequest $request)
{
$article=Auth::user()->articles()->create($request ->all());
$category =Category::find($request ->input('category'));
$article->category()->associate($category)->save();
}

Answer 1

Your relationship type is many to many relotionship, not one to many.
Your models should be like this:
class Article extends Model implements SluggableInterface
{
public function categories()
{
return $this->belongsToMany('App\Category', 'article_category');
}
}
class Category extends Model implements SluggableInterface
{
public function articles()
{
return $this->belongsToMany('App\Article', 'article_category');
}
}
If you want one to many relationship not need 'article_category' table your migrations should like this:
Schema::create('articles',function(Blueprint $table){
$table->integer('id')->increments();
$table->string('title');
$table->text('content');
$table->integer('category_id')->unsigned()->index();
$table->foreign('category_id')->references('id')->on('categories')->onDelete('cascade');
$table->timestamps();
});
and models:
class Article extends Model implements SluggableInterface
{
public function category()
{
return $this->belongsTo('App\Category');
}
}
class Category extends Model implements SluggableInterface
{
public function articles()
{
return $this->hasMany('App\Article');
}
}

Answer 2

Not sure but it looks to me that the relations should be:
articlass Article extends Model implements SluggableInterface
{
public function category()
{
return $this->belongsTo('App\ArticleCategory', 'category_id');
}
}
and
class Category extends Model implements SluggableInterface
{
public function articles()
{
return $this->hasMany('App\ArticleCategory','article_id');
}
}
so it references to the pivot table