Laravel 4,eloquent mysql table design issue - php

Question

I want to be able to design a database which has the following;
customer
--------------
id(int) | name
Company
-------------------------
id(int) | name | location
queue
--------------------------------------------------------------------------------
id (datetime-primary but not auto-increment) | company_id | customer_id | position (not primary but auto-increment)
customer_queue
-----------------------
customer_id | queue_id
public function up()
{
Schema::create('queues', function(Blueprint $table)
{
$table->dateTime('id')->primary(); //dateTime for id since one is genereated every other working day
$table->integer('company_id')->unsigned();
$table->foreign('company_id')->references('id')->on('companies');
$table->integer('customer_id')->unsigned();
$table->foreign('customer_id')->references('id')->on('customers');
$table->increments('position');
$table->time('start_time');
$table->time('end_start');
$table->integer('type');
$table->time('joined_at');
$table->time('left_at');
$table->integer('customer_queue_status');
$table->timestamps();
//$table->primary(array('id', 'position'));
});
//find a way to make position auto-increment without being primary and rather set id to primary without auto-incrementing
}
I'm using laravel 4 with eloquent and it doesn't allow me to specify only primary for id in queue table and then make position auto-increment without being primary.
The error i get is as follows
>This is the error i get
>[Illuminate\Database\QueryException]
SQLSTATE[42000]: Syntax error or access violation: 1068 Multiple primary ke
y defined (SQL: alter table `queues` add primary key queues_id_primary(`id`
))

Answer 1

Increments will automatically try to set the field as a primary key. Therefore you can not use it to increment your position automatically.
If your id field is set to primary, it is by definition unique.
I think there is no way around implementing the auto-increment on your own.
I would do it in some way like this, in your Queue model:
class Queue extends Eloquent {
//....
public static function boot() {
parent::boot();
static::creating(function($queue) {
$position = DB::table('queues')->max('position');
if(is_null($position)) $position = 0;
$position++;
$queue->position = $position;
return true;
});
}
//....
}
This way everytime you save your Queue model it should look for the highest value and increment that by one. In case you have no entry yet it will start with 1.
In your schema, set $table->integer('position')->unique();