PDOException::("SQLSTATE[HY000]: General error: 1215 Cannot add foreign key constraint") - sql

Question

I am using laravel 6.2, connection is SQL. I am creating two tables, with 'one to many relationship.' Table 'users', and 'managers', where each user will have one manager, and each manager will have more than one user.
Below is the user table migration:
<?php
use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;
class CreateUsersTable extends Migration
{
/**
* Run the migrations.
*
* #return void
*/
public function up()
{
Schema::create('users', function (Blueprint $table) {
$table->bigIncrements('id');
$table->string('name');
$table->string('email')->unique();
$table->timestamp('email_verified_at')->nullable();
$table->string('password');
$table->rememberToken();
$table->integer('totalBalance')->default(21);
$table->integer('annualBalance')->default(15);
$table->integer('casualBalance')->default(6);
$table->timestamps();
});
Schema::table('users', function (Blueprint $table) {
$table->bigInteger('manager_id')->unsigned()->index();
$table->foreign('manager_id')->references('id')->on('managers')
->onDelete('cascade');
});
}
/**
* Reverse the migrations.
*
* #return void
*/
public function down()
{
Schema::dropIfExists('users');
}
}
below is the managers migration table:
<?php
use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;
class CreateManagersTable extends Migration
{
/**
* Run the migrations.
*
* #return void
*/
public function up()
{
Schema::create('managers', function (Blueprint $table) {
$table->bigIncrements('id');
$table->string('name');
$table->string('email')->unique();
$table->timestamp('email_verified_at')->nullable();
$table->string('password');
$table->rememberToken();
$table->timestamps();
});
}
/**
* Reverse the migrations.
*
* #return void
*/
public function down()
{
Schema::dropIfExists('managers');
}
}
below is user model:
<?php
namespace App;
use Tymon\JWTAuth\Contracts\JWTSubject;
use Illuminate\Contracts\Auth\MustVerifyEmail;
use Illuminate\Foundation\Auth\User as Authenticatable;
use Illuminate\Notifications\Notifiable;
class User extends Authenticatable implements JWTSubject
{
use Notifiable;
/**
* The attributes that are mass assignable.
*
* #var array
*/
protected $fillable = [
'name', 'email', 'password',
];
/**
* The attributes that should be hidden for arrays.
*
* #var array
*/
protected $hidden = [
'password', 'remember_token',
];
/**
* The attributes that should be cast to native types.
*
* #var array
*/
protected $casts = [
'email_verified_at' => 'datetime',
];
// Rest omitted for brevity
/**
* Get the identifier that will be stored in the subject claim of the JWT.
*
* #return mixed
*/
public function getJWTIdentifier()
{
return $this->getKey();
}
/**
* Return a key value array, containing any custom claims to be added to the JWT.
*
* #return array
*/
public function getJWTCustomClaims()
{
return [];
}
public function setPasswordAttribute($value) {
$this->attributes['password'] = bcrypt($value);
}
public function manager()
{
return $this->belongsTo('App\Manager');
}
}
below is the manager model:
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Manager extends Model
{
protected $primaryKey = 'id';
public function users()
{
return $this->hasMany('App\User');
}
}
I am getting the below error:
I have tried a lot of things, I saw from other questions online, including changing the type of id (from BigInteger, and integer, and changing engine in database.php to ''InnoDB', and splitting the user model to two parts (2nd part for adding the foreign key).
One thing I saw online (but didn't figure out how to implement), is to change the order of timestamp, as some other suggested that this error might be related to this.
Any suggestion?

Answer 1

This is happening because the user migration is run before creating the manager's table. so Change the migration with the following content will help you to create the foreign key under the manager table.
// user migration file
use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;
class CreateUsersTable extends Migration
{
/**
* Run the migrations.
*
* #return void
*/
public function up()
{
Schema::create('users', function (Blueprint $table) {
$table->bigIncrements('id');
$table->string('name');
$table->string('email')->unique();
$table->timestamp('email_verified_at')->nullable();
$table->string('password');
$table->rememberToken();
$table->integer('totalBalance')->default(21);
$table->integer('annualBalance')->default(15);
$table->integer('casualBalance')->default(6);
$table->timestamps();
});
}
/**
* Reverse the migrations.
*
* #return void
*/
public function down()
{
Schema::dropIfExists('users');
}
}
// managers migration file
use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;
class CreateManagersTable extends Migration
{
/**
* Run the migrations.
*
* #return void
*/
public function up()
{
Schema::create('managers', function (Blueprint $table) {
$table->bigIncrements('id');
$table->string('name');
$table->string('email')->unique();
$table->timestamp('email_verified_at')->nullable();
$table->string('password');
$table->rememberToken();
$table->timestamps();
});
Schema::table('users', function (Blueprint $table) {
$table->bigInteger('manager_id')->unsigned()->index();
$table->foreign('manager_id')->references('id')->on('managers')
->onDelete('cascade');
});
}
/**
* Reverse the migrations.
*
* #return void
*/
public function down()
{
Schema::dropIfExists('managers');
}
}