SQLSTATE [HY000]：常规错误：1364字段“ mov_id”没有默认值

Question

have a question related with the 2 tables which are movie and categories

categories are belong to movie which mean i can set many kind of categories for the movie.

So in the categories models, I put this code

public function movie(){
    return $this->belongsTo('App\Movie', 'mov_id');
}

which I want to set categories.mov_id = movie.id

On Controller Part, validation is fine off course show the error message when i put blank. But the problem is cant save to database and display mov_id doesn't have a default value

public function store(Request $request)
{
    $rules = array(
        'cat_title' => 'required'
    );
    $validator = Validator::make(Input::all(), $rules);

    if ($validator->fails()) {
        return Redirect::to('category/create')
            ->withErrors($validator);
    } else {
        $movie = new Category();
        $movie->cat_title = Input::get('cat_title');
        $movie->save();
        Session::flash('message', 'Successfully created!');
        return Redirect::to('category');
    }
}

and last, here is the view file

                   <div class="table-container">
                        <form method="POST" action="{{ route('category.store') }}"  role="form">
                            {{ csrf_field() }}
                            <div class="row">
                                <div class="col-xs-12 col-sm-12 col-md-12">
                                    <div class="form-group">
                                        <input type="text" name="cat_title" id="cat_title" class="form-control input-sm" placeholder="分类">
                                    </div>
                                </div>
                            </div>
                            <div class="row">
                                <div class="col-xs-12 col-sm-12 col-md-12">
                                    <input type="submit"  value="Save" class="btn btn-success btn-block">
                                    <a href="{{ route('category.index') }}" class="btn btn-info btn-block" >Back</a>
                                </div>

                            </div>
                        </form>
                    </div>

Category schema

        Schema::create('category', function (Blueprint $table) {
        $table->increments('id');
        $table->string('cat_title');
        $table->integer('mov_id');
        $table->timestamps();
    });

The image of error message:-

Answer 1

The error msg tells you exactly what the problem is. You are trying to insert a category record, but your form does not include a mov_id value. Your schema specifies that mov_id is an integer, but does not specify any default value, nor that it can be null. So Laravel does not know what to use for mov_id if you don't tell it, so it can't create a record.

The quick fix is to update your schema to allow null values for mov_id :

$table->integer('mov_id')->nullable();

But I think you're going to have bigger problems. A category probably should not have a movie ID at all - that would mean that every category could have at most 1 movie.

I think what you really want is a many-to-many relationship between movies and categories. That means one movie can have many categories, and one category can be assigned to many movies.

The Laravel docs describe it well and include an example . You'll need to update your Laravel relationships:

// Category model
public function movie() {
    return $this->belongsToMany('App\Movie');
}

// Movie model
public function category() {
    return $this->belongsToMany('App\Category');
}

And your schema:

Schema::create('movies', function (Blueprint $table) {
    $table->increments('id');
    $table->string('title');
    // ... etc
});

Schema::create('categories', function (Blueprint $table) {
    $table->increments('id');
    $table->string('cat_title');
    // ... etc
});

Schema::create('category_movie', function (Blueprint $table) {
    $table->integer('category_id');
    $table->integer('movie_id');
});