Index: wordpress/wp-includes/meta.php
===================================================================
--- wordpress/wp-includes/meta.php	(revision 18474)
+++ wordpress/wp-includes/meta.php	(working copy)
@@ -322,6 +322,131 @@
 }
 
 /**
+ * Update meta data by meta ID
+ *
+ * @since 3.3.0
+ *
+ * @uses get_metadata_by_mid() Calls get_metadata_by_mid() to fetch the meta key, value
+ *		and object_id of the given meta_id.
+ *
+ * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
+ * @param int $meta_id ID for a specific meta row
+ * @param string $meta_value Metadata value
+ * @param string $meta_key Optional, you can provide a meta key to update it
+ * @return bool True on successful update, false on failure.
+ */
+function update_metadata_by_mid( $meta_type, $meta_id, $meta_value, $meta_key = false ) {
+	global $wpdb;
+	
+	// Make sure everything is valid.
+	if ( ! $meta_type )
+		return false;
+
+	if ( ! $meta_id = absint( $meta_id ) )
+		return false;
+
+	if ( ! $table = _get_meta_table( $meta_type ) )
+		return false;
+		
+	$column = esc_sql($meta_type . '_id');
+	$id_column = 'user' == $meta_type ? 'umeta_id' : 'meta_id';
+
+	// Fetch the meta and go on if it's found.
+	if ( $meta = get_metadata_by_mid( $meta_type, $meta_id ) ) {
+		$original_key = $meta->meta_key;
+		$object_id = $meta->{$column};
+		
+		// If a new meta_key (last parameter) was specified, change the meta key,
+		// otherwise use the original key in the update statement.
+		if ( false === $meta_key ) {
+			$meta_key = $original_key;
+		} elseif ( ! is_string( $meta_key ) ) {
+			return false;
+		}
+			
+		// Sanitize the meta
+		$meta_value = sanitize_meta( $meta_key, $meta_value, $meta_type );
+		$meta_value = maybe_serialize( $meta_value );
+		
+		// Format the data query arguments.
+		$data = array(
+			'meta_key' => $meta_key,
+			'meta_value' => $meta_value
+		);
+		
+		// Format the where query arguments.
+		$where = array();
+		$where[$id_column] = $meta_id;
+		
+		// Run the update query, all fields in $data are %s, $where is a %d.
+		$result = (bool) $wpdb->update( $table, $data, $where, '%s', '%d' );
+		
+		// Clear the caches.
+		wp_cache_delete($object_id, $meta_type . '_meta');
+		
+		// Users cache stores usermeta that must be cleared.
+		if ( 'user' == $meta_type )
+			clean_user_cache($object_id);
+
+		return $result;
+	}
+	
+	// And if the meta was not found.
+	return false;
+}
+
+/**
+ * Delete meta data by meta ID
+ *
+ * @since 3.3.0
+ *
+ * @uses get_metadata_by_mid() Calls get_metadata_by_mid() to fetch the meta key, value
+ *		and object_id of the given meta_id.
+ *
+ * @param string $meta_type Type of object metadata is for (e.g., comment, post, or user)
+ * @param int $meta_id ID for a specific meta row
+ * @return bool True on successful delete, false on failure.
+ */
+function delete_metadata_by_mid( $meta_type, $meta_id ) {
+	global $wpdb;
+	
+	// Make sure everything is valid.
+	if ( ! $meta_type )
+		return false;
+
+	if ( ! $meta_id = absint( $meta_id ) )
+		return false;
+
+	if ( ! $table = _get_meta_table( $meta_type ) )
+		return false;
+	
+	// object and id columns
+	$column = esc_sql($meta_type . '_id');
+	$id_column = 'user' == $meta_type ? 'umeta_id' : 'meta_id';
+
+	// Fetch the meta and go on if it's found.
+	if ( $meta = get_metadata_by_mid( $meta_type, $meta_id ) ) {
+		$object_id = $meta->{$column};
+		
+		// Run the query, will return true if deleted, false otherwise
+		$result = (bool) $wpdb->query( $wpdb->prepare( "DELETE FROM $table WHERE $id_column = %d LIMIT 1;", $meta_id ) );
+		
+		// Clear the caches.
+		wp_cache_delete($object_id, $meta_type . '_meta');
+		
+		// Users cache stores usermeta that must be cleared.
+		if ( 'user' == $meta_type )
+			clean_user_cache($object_id);
+			
+		return $result;
+
+	}
+	
+	// Meta id was not found.
+	return false;
+}
+
+/**
  * Update the metadata cache for the specified objects.
  *
  * @since 2.9.0