Laravel Foreign Key Table

Foreignkey

users migration

public function up(): void
{
  Schema::create('users', function (Blueprint $table) {
    $table->id();
    $table->string('name');
    $table->timestamps();
  });
}

public function down(): void
{
  Schema::dropIfExists('users');
}

profiles migration

public function up(): void
{
  Schema::create('profiles', function (Blueprint $table) {
    $table->id();
    $table->string('image');
    $table->unsignedBigInteger('user_id');
    $table->foreign('user_id')->references('id')->on('users')->onDelete('cascade')
     ->onUpdate('cascade');
    $table->timestamps();
  });
}

public function down(): void
{
    Schema::table('profiles', function (Blueprint $table) {
        $table->dropForeign(['user_id']); // Drop Foreign Key first
    });

    Schema::dropIfExists('profiles');
}

If you drop the profiles table, Laravel will handle dropping the foreign key automatically. But in some MySQL versions, it may throw an error. To be safe, you can explicitly drop the foreign key before dropping the table:

Foreign Key Constraints

Laravel makes relationships easy:

$table->foreignId('user_id')->constrained();

(OR)

$table->unsignedBigInteger('user_id');
$table->foreign('user_id')->references('id')->on('users');

Add onDelete / onUpdate behavior:

$table->foreignId('user_id')
->constrained()
->onDelete('cascade')
->onUpdate('cascade');

(OR)

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

Set Foreign Key to NULL on Delete

$table->foreignId('user_id')
->nullable()
->constrained()
->nullOnDelete(); // shorthand for onDelete('set null')

(OR)

$table->unsignedBigInteger('user_id')->nullable(); // must be nullable
$table->foreign('user_id')
->references('id')->on('users')
->onDelete('set null');