function zimo_schema() {
  $schema['zimo'] = array(
    'description' => 'Stores example person entries for demonstration purposes.',
    'fields' => array(
      'pid' => array(
        'type' => 'serial',
        'not null' => TRUE,
        'description' => 'Primary Key: Unique person ID.',
       ),

      'name' => array(
        'type' => 'varchar',
        'length' => 255,

       ),

      'paiddate' => array(
       'type' => 'date',

      ),
      'amount' => array(
        'type' => 'bigint',

       ),
    ),
    'primary key' => array('pid'),

  );

  return $schema;
}

namespace DrupalzimoForm;

use DrupalCoreFormFormBase;
use DrupalCoreFormFormStateInterface;
use DrupalzimoZimoStorage;

/**
 * Simple form to add an entry, with all the interesting fields.
 */
class ZimoAddForm extends FormBase {

  /**
   * {@inheritdoc}
   */
  public function getFormId() {
    return 'zimo_add_form';
  }

  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state) {
    $form = array();

    $form['message'] = array(
      '#markup' => $this->t('Add an entry to the Zimo Database table.'),
    );

    $form['add'] = array(
      '#type' => 'fieldset',
      '#title' => t('Add a person entry'),
    );
    $form['add']['name'] = array(
      '#type' => 'textfield',
      '#title' => t('Name'),
      '#size' => 15,
    );
    $form['add']['paiddate'] = array(
      '#type' => 'date',
      '#title' => t('Paid Date'),
    );
    $form['add']['amount'] = array(
      '#type' => 'textfield',
      '#title' => t('Paid Amount')
    );
    $form['add']['submit'] = array(
      '#type' => 'submit',
      '#value' => t('Add'),
    );

    return $form;
  }