如何在Laravel 5.1中更新hasMany关系

Question

I am totally new on Laravel, and I have implement the User table provided by Laravel Auth , and also I have create a table for the user meta data that is a Key Value pare table .

The user meta table is created by the following code :

use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class UserMeta extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('user_meta', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('user_id')->unsigned();
            $table->char('meta_key', 255);
            $table->longText('meta_value')->nullable();
            $table->timestamps();

            $table->foreign('user_id')->references('id')->on('users')->onUpdate('cascade')->onDelete('cascade');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::drop('user_meta');
    }
}

In my User model I have the following method:

public function meta() {
    return $this->hasMany('App\Models\UserMeta');
}

and inside my UserMeta model I have the following method:

public function user() {
    return $this->belongsTo('App\User');
}

Until now anything is fine. So, when I register a new user I perform the following actions:

$user = User::create(
    [
        'name'     => $data['name'],
        'email'    => $data['email'],
        'password' => bcrypt( $data['password'] ),
    ]
);

if ( $user ) {

    $telephone_number = new UserMeta;
    $telephone_number->user()->associate($user);
    $telephone_number->meta_key = 'telephone_number';
    $telephone_number->meta_value = $data['telephone_number'];
    $telephone_number->save();

    $company = new UserMeta;
    $company->user()->associate($user);
    $company->meta_key = 'company';
    $company->meta_value = $data['company'];
    $company->save();

    $web_site = new UserMeta;
    $web_site->user()->associate($user);
    $web_site->meta_key = 'web_site';
    $web_site->meta_value = $data['web_site'];
    $web_site->save();

}

return $user;

I suppose that should be a better way to perform that same actions, but I don't know what is the other way :( :)

So, the above code works very nice for me, but now the problem is with the value update. In this case, how can I update the Meta Data when I update the user profile ?

In my update method of my UserControler , I perform the following actions:

$user = User::where( 'id', '=', $id )->first();

$user->name  = $request->input( 'name' );
$user->email = $request->input( 'email' );
$user->password = bcrypt( $request->input( 'password' ) );

$user->save();

My $request->input(); has the following extra fields that corresponding to meta values telephone_number , web_site , company .

So, how can I update the meta values in the user_meta table ?

Answer 1

Looping through values

Firstly, you are right that you could loop through the three keys in your create method to:

// Loop through all the meta keys we're looking for
foreach(['telephone_number', 'web_site', 'company'] as $metaKey) {
    $meta = new UserMeta;
    $meta->meta_key = $metaKey;
    $meta->meta_value = array_get($data, $metaKey);
    $meta->save();
}

The Update Method: Approach One

Then, in your update method

// Loop through all the meta keys we're looking for
foreach(['telephone_number', 'web_site', 'company'] as $metaKey) {
    // Query for the meta model for the user and key
    $meta = $user->meta()->where('meta_key', $metaKey)->firstOrFail();
    $meta->meta_value = array_get($data, $metaKey);
    $meta->save();
}

Note the firstOrFail() to end the query. This is just me being strict. If you wanted to add a meta value if it didn't exist, then you could replace that line with

// Query for the meta model for the user and key, or
// create a new one with that key
$meta = $user->meta()->where('meta_key', $metaKey)
    ->first() ?: new UserMeta(['meta_key' => $metaKey]);

The Update Method: Approach Two

This approach is a little more efficient, but a more complex (but also potentially teaches about a cool feature of Eloquent!).

You could load in all of the meta keys first (see lazy eager loading ).

// load the meta relationship
$user->load('meta');

// Loop through all the meta keys we're looking for
foreach(['telephone_number', 'web_site', 'company'] as $metaKey) {
    // Get the first item with a matching key from the loaded relationship
    // Or, create a new meta for this key
    $meta = $user->meta
        ->first(function($item) use ($metaKey) { 
            return $item->meta_key === $metaKey; 
        }) ?: new UserMeta(['meta_key' => $metaKey]);
    $meta->meta_value = array_get($data, $metaKey);
    $meta->save();
}