WordPress: update_option, don’t update empty options?

How would I go about not letting empty data into wordpress?

<?php 
foreach($_POST['eirepanel_inline_ads_options_name'] as  $post_eirepanel_inline_ads_options_name):
if(empty($post_eirepanel_inline_ads_options_name)): 
    echo 'empty';
else: 
    update_option('eirepanel_inline_ads_options', $_POST);
    $eirepanel_inline_ads_options = get_option('eirepanel_inline_ads_options');
endif; 
endforeach;
?>

More importantly, you should not let *untrusted, unsanitized $_POST data* into WordPress.

But I think the issue is that you’re updating the option with the entire $_POST data, instead of the appropriate array key:

update_option('eirepanel_inline_ads_options', $_POST);

Should probably be something like:

update_option('eirepanel_inline_ads_options', $_POST['eirepanel_inline_ads_options_name']);

Are your Plugin options discrete (one DB entry per option), or an options array?

EDIT

Since you’re using an options array, the correct approach would be:

1. Define an array to hold the $_POST data ( $input = array() )
2. Define an array to get the current settings from the DB ( $valid_input = array() )
3. Sanitize the $_POST data
4. Update the $valid_data array with the sanitized $input array
5. Pass the updated $valid_data back to the DB

e.g.

$input = ( isset( $_POST ) ? $_POST : false );
$valid_input = get_option( 'eirepanel_inline_ads_options' );

foreach ( $input as $key ) {
   // sanitize data here
}

$valid_input = array_merge( $valid_input, $input );

update_option( 'eirepanel_inline_ads_options', $valid_input );

Just quick and dirty, but should give you an idea.

Also: using the Settings API would be especially helpful here.