How to update serialized post meta?

Question

I have serialized post meta. And i want to update single meta key. It looks like this:

In array:

$kisiArray = array(
   'option1' => 'foo',
   'option2' => 'bar',
   'option3' => 'apple',
   'option4' => 'orange'
);

I want to update only 'option3' to 'peach' so i am using update_post_meta function.

update_post_meta( $post_id, 'themeOps', ??? );

But i don't know what i must put the meta_value section. When i pust peach, it changes all meta keys to peach.

Answer 1

You must read custom field themeOps first, update index option3 in array and then save/update whole array.

$kisiArray = get_post_meta( $post_id, 'themeOps' );
$kisiArray['option3'] = 'peach';
update_post_meta( $post_id, 'themeOps', $kisiArray );

---

Update (sort by custom field)

$args = array(
    'post_type'  => 'post',
    'meta_key'   => 'themeOps_option3',
    'orderby'    => 'meta_value_num',
    'order'      => 'ASC',
);
$query = new WP_Query( $args );

More examples you find in Codex