# Custom field default value with counter

I have a custom post type called machine and a custom field 'reference_number' what I want is to add a default value to the custom field when creating a new machine and show this value before the save.

Here is what I came up with so far.

function set_default_meta($post_ID){$current_field_value = get_post_meta($post_ID,'reference_number',true); // this needs to be like, machine 1, machine 2, ..$default_meta = 'machine ';
if ($current_field_value == '' && !wp_is_post_revision($post_ID)){
add_post_meta($post_ID,'reference_number',$default_meta,true);
}
return $post_ID; } add_action('wp_insert_post','set_default_meta');  The code works and add 'machine ' value to the custom field, but only after saving the post. how can I show it when just starting to add the post. and How can I add a counter variable that increase by one in every new post. Thanks ## EDIT Thanks so much to @s_ha_dum for code, I also asked a question at Pods forum and they helped a lot with the global variable. So the final code is to 1- add global variable as default in pods admin  {@globals.reference_number}  2- add this code in functions.php // Set reference number to be dynamicaly increased every time machine created. function get_next_reference_number() { global$wpdb;
$ref =$wpdb->get_var("SELECT max(cast(meta_value as unsigned)) FROM wp_postmeta WHERE meta_key='reference_number'");
$GLOBALS[ 'reference_number' ] = (!empty($ref)) ? $ref + 1 : 1; } add_action('wp_insert_post','get_next_reference_number');  And it works. • How do you show the field? In a metabox? Or are you using the Custom Fields default box? – fuxia Jun 3 '13 at 5:21 • I use podsframework.org for creating custom fields. it has a default field option but with no option for add a counter so may be I can make it outside the plugin if this possible. – Ahmad Ajmi Jun 3 '13 at 5:49 ## 1 Answer I don't know how the pods framework works so I can't tell you how to set the value but I can get you started. First, don't store your entire "machine %n" string. The "machine" part it going to be the same for all entries, correct? Then just save the "%n". Now, when you need to add a new post ... function get_next_reference_number() { global$wpdb;
$ref =$wpdb->get_var("SELECT MAX(meta_value) FROM {$wpdb->postmeta} WHERE meta_key = 'reference_number'"); return (!empty($ref)) ? \$ref + 1 : 1;
}


Hopefully you can work that into your Pods code.

• Thanks so much, it works with as you said. I updated my question with the full code. – Ahmad Ajmi Jun 14 '13 at 14:42