Does laravel automatically add the index to the primary keys?

[SenaJp]

I'm creating my tables and I would like to know if I need to add the index or not to my primary keys.

[shaedrich]

$table->id() only calls \Illuminate\Database\Schema\Blueprint::bigIncrements() as UNSIGNED BIGINT AUTO_INCREMENT. In order to make it an index explicitly, you have to call \Illuminate\Database\Schema\ColumnDefinition::primary() on the result of $table->id() like so:

Schema::table('users', function (Blueprint $table) {
    $table->id()->primary();
});

However, the docs repeatedly call this

equivalent column as a primary key:

meaning, that MySQL will implicitly add an index itself under the hood.

[henzeb]

Isn't id() not already making it a primary? According to the docs it is using bigIncrements under the hood and that does make it a primary key. https://laravel.com/docs/10.x/migrations#column-method-id

[shaedrich]

Yeah, that's actually a little confusing about the docs: It never explictly says, it sets any index with that method. However, it repeatedly states, that this is "equivalent" of it.

[iazaran]

Using $table->id(); is enough to make ID, auto increment and primary key. Take a look at the DB DDL for a simple table result:

CREATE TABLE `tests` (
  `id` bigint unsigned NOT NULL AUTO_INCREMENT,
  `created_at` timestamp NULL DEFAULT NULL,
  `updated_at` timestamp NULL DEFAULT NULL,
  PRIMARY KEY (`id`),
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci

But for indexing, in MySQL, a primary index is automatically created, and finally, it's actually not necessary to create an index on the primary key column.

[luishenrique98]

Thank you @SenaJp for helping the community, God bless you!