Improved meta API

[scribu]

Yes, discussions on the topic can be seen here:

#5183 #2659

But they focus on table structure, not on the api. Hence, the new ticket.

Discussions on the api (as well as the table structure) can be found on wp-hackers: and also on wp-hackers: ​1 ​2

This patch:

• replaces postmeta with a generic meta table

• the meta table has enum as meta_type for better performance

• implements these functions:

register_meta_type($meta_type);

add_metadata($meta_type, $object_id, $meta_key, $meta_value, $unique = false);

update_metadata($meta_type, $object_id, $meta_key, $meta_value, $prev_value = '');

delete_metadata($meta_type, $object_id, $meta_key = '', $meta_value = '');

get_metadata($meta_type, $object_id, $key = '', $single = false);

Notice that $meta_key is optional for delete_metadata() and get_metadata().

• maps these functions:

add_post_meta();

update_post_meta();

delete_post_meta();

get_post_meta();

get_post_custom();

plugin for basic testing

first draft

What's still needed is code to migrate data from postmeta to meta.

plugin for basic testing

code to migrate data to new table

Some thoughts I wrote a while back:
​http://blog.ftwr.co.uk/archives/2009/07/23/a-better-meta-api-for-wordpress/

We now have a generic meta API. How do we make it more flexible?

Closing since we're not doing generic meta.