How I can put composite keys in models in Laravel 5?

Php Problem Overview

I have in my DataBase a table with two primary keys (id and language_id) and I need put it in my models. The default primaryKey in Models (Model.php in Laravel 5) is id, and I want that the primaryKeys will be id and id_language. I tried put it with arrays or a String with ',' but it doesn't work. It says me that the array could not be converted in String.

Php Solutions

Solution 1 - Php

I wrote this simple PHP trait to adapt Eloquent to handle composite keys:

<?php

namespace App\Model\Traits; // *** Adjust this to match your model namespace! ***

use Illuminate\Database\Eloquent\Builder;

trait HasCompositePrimaryKey
{
    /**
     * Get the value indicating whether the IDs are incrementing.
     *
     * @return bool
     */
    public function getIncrementing()
    {
        return false;
    }

    /**
     * Set the keys for a save update query.
     *
     * @param  \Illuminate\Database\Eloquent\Builder $query
     * @return \Illuminate\Database\Eloquent\Builder
     */
    protected function setKeysForSaveQuery(Builder $query)
    {
        foreach ($this->getKeyName() as $key) {
            // UPDATE: Added isset() per devflow's comment.
            if (isset($this->$key))
                $query->where($key, '=', $this->$key);
            else
                throw new Exception(__METHOD__ . 'Missing part of the primary key: ' . $key);
        }

        return $query;
    }

    // UPDATE: From jessedp. See his edit, below.
    /**
     * Execute a query for a single record by ID.
     *
     * @param  array  $ids Array of keys, like [column => value].
     * @param  array  $columns
     * @return mixed|static
     */
    public static function find($ids, $columns = ['*'])
    {
        $me = new self;
        $query = $me->newQuery();
        foreach ($me->getKeyName() as $key) {
            $query->where($key, '=', $ids[$key]);
        }
        return $query->first($columns);
    }
}

Place that in a Traits directory under your main model directory, then you can add a simple one-liner to the top of any composite-key model:

class MyModel extends Eloquent {
    use Traits\HasCompositePrimaryKey; // *** THIS!!! ***

    /**
     * The primary key of the table.
     * 
     * @var string
     */
    protected $primaryKey = array('key1', 'key2');

    ...

addded by jessedp:
This worked wonderfully for me until I wanted to use Model::find ... so the following is some code (that could probably be better) that can be added to the hasCompositePrimaryKey trait above:

protected static function find($id, $columns = ['*'])
{
    $me = new self;
    $query = $me->newQuery();
    $i=0;

    foreach ($me->getKeyName() as $key) {
        $query->where($key, '=', $id[$i]);
        $i++;
    }

    return $query->first($columns);
}

Update 2016-11-17

I'm now maintaining this as part of an open-source package called LaravelTreats.

Update 2020-06-10

LaravelTreats is dead, but enjoy the code anyways :)

Over the years, a few in-depth use cases have been brought to my attention where this breaks down. This should work for the vast majority of use cases, but know that if you try to get fancy, you might have to rethink your approach.

Solution 2 - Php

You can't. Eloquent doesn't support composite primary keys.

Here's a Github issue regarding this.

Solution 3 - Php

It seems it changed, since this one works with at least Laravel 5.1:

$table->primary(['key1', 'key2']);

I just run the migration and what i see in the database fits to what i put in code above (of course the name fields above are just for presentation purposes).

Update: this is true for migrations, but as soon as you want to insert via eloquent it doesn´t work with composite keys and will never do (last entry):

https://github.com/laravel/framework/issues/5517

Solution 4 - Php

In migrations you can simply define composite primary keys for a table as @erick-suarez and @sba said, in your Schema::create or Schema::table block write $table->primary(['key1', 'key2']);

In the Eloquent model that represents that table you can't directly use that composite key with Eloquent methods e.g. find($key) nor save($data) but you can still retrieve the model instance for viewing purposes using

$modelObject = ModelName->where(['key1' => $key1, 'key2' => $key2])->first();

And if you want to update a record in that table you can use QueryBuilder methods like this:

ModelName->where(['key1' => $key1, 'key2' => $key2])->update($data);

Where $data is the data associative array you want to update your model with like so ['attribute1' => 'value1', ..].

Note: You can still use Eloquent relationships safely for retrieval with such models, as they are commonly used as pivot tables that break many-to-many relationship structures.

Solution 5 - Php

An easy solution, that works well for me (Laravel 5.7):

Define one of the primary keys in the Model:

class MyTable extends Model
{
        protected $primaryKey = 'user_id';
        protected $table = 'my_table';
        protected $fillable = ['user_id', 'post_id', 'flag'];

So pass both primary keys in the Controller, here I used in the first of the two parameters of the updateOrCreate method, that receives two arrays:

Controller:

public function post_foo(Request $request)
{
//PK1 is user_id, PK2 is post_id
//flag - is the field that has its value changed

$task = MyTable::updateOrCreate(
    ['user_id' => $request->header('UID'),'post_id' => $request->input('post_id')],
    ['user_id' => $request->header('UID'),'post_id' => $request->input('post_id'),'flag' => $request->input('flag')]
    );
    return $task;
}

Explaining the solution:

The problem of you not having an id column as the primary key is solved with only one primary key in Model, the correct row in DB is found with the two primary keys in the Controller.

Solution 6 - Php

you can try to use following module

https://github.com/maksimru/composite-primary-keys

simply add HasCompositePrimaryKey trait to your model and specify array value as primary key

Solution 7 - Php

Try looking at this documentation for inserting many to many relations with CK

<https://laravel.com/docs/5.2/eloquent-relationships#inserting-many-to-many-relationships>

Edit: some extra info
As you can see in the documentation, the attach and detach functions create the links needed in the CK intermediate table. So yo don't have to create them yourself ;)

In your case it would be model->languages()->attach(language_id)

Solution 8 - Php

https://laravel.com/docs/5.3/migrations#columns

Yes, u can.

i share my migration code:

    <?php

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

class RegistroEmpresa extends Migration {

	/**
	 * Run the migrations.
	 *
	 * @return void
	 */
	public function up()
	{
		Schema::create('registro_empresa', function(Blueprint $table)
		{
			$table->string('licencia',24);
			$table->string('rut',12);
			$table->string('nombre_empresa');
			$table->string('direccion');
			$table->string('comuna_Estado');
			$table->string('ciudad');
			$table->string('pais');
			$table->string('fono');
			$table->string('email');
			$table->string('paginaweb');
			$table->string('descripcion_tienda');
			$table->string('monedauso');
			$table->timestamps();
			$table->primary(['licencia', 'rut']);
		});
	}

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

}

Content Type	Original Author	Original Content on Stackoverflow
Question	Sergioh Lonet	View Question on Stackoverflow
Solution 1 - Php	mopo922	View Answer on Stackoverflow
Solution 2 - Php	lukasgeiter	View Answer on Stackoverflow
Solution 3 - Php	sba	View Answer on Stackoverflow
Solution 4 - Php	Mohyaddin Alaoddin	View Answer on Stackoverflow
Solution 5 - Php	Fellipe Sanches	View Answer on Stackoverflow
Solution 6 - Php	Maksim Martianov	View Answer on Stackoverflow
Solution 7 - Php	Hibbem	View Answer on Stackoverflow
Solution 8 - Php	Erick Suarez	View Answer on Stackoverflow