WordPress.org

Ready to get started?Download WordPress

Codex

Attention Interested in functions, hooks, classes, or methods? Check out the new WordPress Code Reference!

UnMuify the plugin shared tables

In WPMU the runtime muifys the wpdb->prefix, changing it from the default wp_ prefix to wp_x_ where x = 1...n; as this is usually needed to convert plugins that know about a single blog to one that can deal with many.

This normally works fine, but causes issues where a plugin actually wants a global table, not a per blog one.

If you need a plugin to use a global table, then you could either modify the plugin's code to use $wpdb->base_prefix (which is the base table prefix, probably wp_) or you can possibly add lines similar to these at the start and end of the plugin files rather than editing all the code inline:

<?php
$wpdb->my_global_table = $wpdb->base_prefix . 'my_global_table';
$wpdb->my_other_global_table = $wpdb->base_prefix . 'my_other_global_table';

// then you can use those variables throughout your plugin like so

$my_query = $wpdb->prepare( "SELECT field1 FROM {$wpdb->my_global_table} WHERE my_id = %d", $my_id );
?>