Answers for "down function foreign key laravel"

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();
});

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 string laravel

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