Laravel make migration with foreign key failed-CodePudding

I have a project named Partner

I need to create developers table and two other tables branches and projects

And every Developer has many branches and has many projects

So I created this migration files:

Developers

public function up()
{
    Schema::create('developers', function (Blueprint $table) {
        $table->id();
        $table->string('company_name', 100);
        $table->string('responsible_name', 100);
        $table->string('email', 100);
        $table->string('phone', 100);
        $table->string('hotline', 100)->nullable();
        $table->timestamps();
    });
}

Branches

public function up()
{
    Schema::create('branches', function (Blueprint $table) {
        $table->id();
        $table->integer('developer_id')->unsigned();
        $table->string('name', 100);
        $table->string('address', 100);
        $table->string('location', 100);
        $table->string('phone', 100);
        $table->timestamps();
        $table->foreign('developer_id')->references('id')->on('developers')->onDelete('cascade');
    });
}

Projects

public function up()
{
    Schema::create('projects', function (Blueprint $table) {
        $table->id();
        $table->integer('developer_id')->unsigned();
        $table->string('name', 100);
        $table->string('type', 100);
        $table->string('address', 100);
        $table->string('location', 100);
        $table->string('availability', 100);
        $table->text('payment_plan');
        $table->string('brochure', 100)->nullable();
        $table->timestamps();
        $table->foreign('developer_id')->references('id')->on('developers')->onDelete('cascade');
    });
}

But when I ran php artisan migrate I got this error

SQLSTATE[HY000]: General error: 1005 Can't create table `partner`.`branches` (errno: 150 "Foreign key constraint is incorrectly formed") (SQL: alter table `branches` add constraint `branches_developer_id_foreign` foreign key (`developer_id`) references `developers` (`id`) on delete cascade)

What is the wrong with the form of the foreign key?

CodePudding user response：

You can use foreign key in migration without predefine field :

$table->foreignId('developer_id')->constrained('developers')->onDelete('cascade');

and remove this line :

$table->integer('developer_id')->unsigned();