PHP

laravel foreign key

Schema::table('posts', function (Blueprint $table) {
    $table->unsignedBigInteger('user_id');

    $table->foreign('user_id')->references('id')->on('users');
});
OR
Schema::table('posts', function (Blueprint $table) {
    $table->foreignId('user_id')->constrained();
});

foreign key in Laravel

// one_line code for foreign in laravel
$table->foreignId('user_id')->constrained()->onDelete('cascade');

laravel foreign key constraint

public function up()
{
    Schema::create('replies', function (Blueprint $table) {
        $table->bigIncrements('id');
        $table->text('body');
        $table->unsignedBigInteger('question_id');
        $table->integer('user_id')->unsigned();
        $table->foreign('question_id')->references('id')->on('questions')->onDelete('cascade');
        $table->timestamps();
    });
}

laravel foreign key

//acording to laravel 7>=

Schema::table('posts', function (Blueprint $table) {
    $table->foreignId('user_id')->constrained();
});

//for deffirent table
$table->foreignId('user_id')->constrained('users');

//for taking action
$table->foreignId('user_id')
      ->constrained()
      ->onUpdate('cascade')
      ->onDelete('cascade');

foreign key laravel migration

$table->foreign('column_name')->references('id')->on('table_name')->onDelete('cascade');

laravel 8 foreign key

Schema::table('posts', function (Blueprint $table) {
    $table->foreignId('user_id')->constrained();
});

laravel foreign key

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

laravel foreign

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

foreign key in laravel 9

Firstly you have to make your user_id field an index:

$table->index('user_id');
After that you can create a foreign key with an action on cascade:

$table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
If you want to do that with a new migration, you have to remove the index and foreign key firstly and do everything from scratch.

On down() function you have to do this and then on up() do what I've wrote above:

$table->dropForeign('lists_user_id_foreign');
$table->dropIndex('lists_user_id_index');
$table->dropColumn('user_id');

How to create foreign key in Laravel

$table->foreign('category_id')->references('id')->on('categories')->onUpdate('cascade')->onDelete('cascade');

foreign key string laravel

Schema::table('portfolios', function (Blueprint $table) {
            $table->string('filter_alias');
            $table->foreign('filter_alias')->cascadeOnDelete()->references('alias')->on('filters');
        });