Question

i’m still working on my own drupal 7 module, and i’m having some trouble. I’m trying to load database content to dropdown option (select), i have read and write the same code from drupal example, but my database still not loading, only empty option.
what i’m asking is there anything wrong on my code or is there any faster way to load database to dropdown option other than the drupal example???

here the code i’m working on

function prod_entry_load($entry = array()) {
  $select = db_select('aa_1122','aa');
  $select->fields('aa');

  foreach ($entry as $field => $value) {
    $select->condition($field, $value);
  }
  return $select->execute()->fetchAll();
}

function prod(){
    return drupal_get_form('prod_form');
}
function prod_form($form_state){
  $form = array(
      '#prefix' => '<div id="updateform">',
      '#suffix' => '</div>',
  );

  $entries = prod_entry_load();
  $keyed_entries = array();
  if (empty($entries)) {
    $form['no_values'] = array(
      '#value' => t("No entries exist in the table dbtng_example table."),
    );
    return $form;
  }

  foreach ($entries as $entry) {
    $options[$entry->no] = t("@no: @name ", array('@no' => $entry->no, '@name' => $entry->name));
    $keyed_entries[$entry->no] = $entry;
  }
  $default_entry = !empty($form_state['values']['no']) ? $keyed_entries[$form_state['values']['no']] : $entries[0];

  $form_state['entries'] = $keyed_entries;

  $form['no'] = array(
    '#type' => 'select',
    '#title' => t('Choose'),
    '#default_value' => $default_entry->no,
    '#ajax' => array(
        'wrapper' => 'updateform',
        'callback' => 'prod_form_update_callback',
    ),
  );
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => 'Submit',
    '#ajax' => array(
      'callback' => 'ajax_alert',
    ),
  );
  return $form;
}

function prod_form_update_callback($form, $form_state) {
  $entry = $form_state['entries'][$form_state['values']['no']];  
  foreach (array('name') as $item) {
    $form[$item]['#value'] = $entry->$item;
  }
  return $form;
}

Answer 1

You’ve just forgotten to add the #options key to your select element, the code should read like this:

$form['no'] = array(
  '#type' => 'select',
  '#title' => t('Choose'),
  '#default_value' => $default_entry->no,
  '#options' => $options, // This is the bit that was missing
  '#ajax' => array(
    'wrapper' => 'updateform',
    'callback' => 'prod_form_update_callback',
  ),
);

You could shorten your query/options code slightly using a combination of string concatenation in MySQL and the db fetchAllKeyed() method:

$query = db_select('aa_1122', 'aa')->fields('aa', array('no'));
$query->addExpression("CONCAT(no, ': ', name)", 'display');
$options = $query->execute()->fetchAllKeyed();