formd8v2.install

<?php

use Drupal\Core\Database\Database;

function formd8v2_schema() {
  $schema['form_1'] = array(
    // Example (partial) specification for table "node".
    'description' => 'The base table for forms.',
    'fields' => array(
      'id' => array(
        'description' => 'The primary identifier for a form.',
        'type' => 'serial',
        'not null' => TRUE,
      ),
      'first_name' => array(
        'description' => 'The First name',
        'type' => 'varchar',
        'length' => 32,
        'not null' => TRUE,
        'default' => '',
      ),
      'last_name' => array(
        'description' => 'The last name',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'gender' => array(
        'description' => 'The gender name',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),
      'birth_date' => array(
        'description' => 'The birth date',
        'type' => 'int',
        'length' => 127,
        'not null' => TRUE,
      ),
      'email' => array(
        'description' => 'The email',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ),

    ),

    'primary key' => array('id'),
  );
  return $schema;
}

function formd8v2_update_8001(){
  $column = array(
    'description' => 'fid',
    'type' => 'int',
    'length' => 20,
    'not null' => FALSE,
    );
  $schema = Database::getConnection()->schema();
  $schema ->addField('form_1','fid',$column);
}