Okay I have this working (without multiple database calls). Here’s is some pseudocode of how I did it:
Because my plugin is currently not written with classes, I used a global variable. A class variable would probably be better.
For the retrieval of the data, I didn’t change anything, because on the first call to the database, the results are cached so each subsequent field just pulls from the cache.
For the saving of the data, I did it in two steps.
The first step saves the updated data to the global variable on CMB2’s override hook in an array of ( post_meta_field_id => value ). Some of my fields are saved in a custom table, and some are saved using WordPress’ tables via CMB2 (mainly, repeated groups). So I have a check for if the field is part of the custom table or not.
The 2nd step is triggered through WP’s save_post hook to actually save to the database, from the global variable I created.
add_filter('cmb2_override_meta_remove', 'your_save_meta_data_function', 10, 2);
add_filter('cmb2_override_meta_save', 'your_save_meta_data_function', 10, 2);
function your_save_meta_data_function( $override, $a ) {
// if not the right post type, return what we got in
if ( get_post_type() != 'your_post_type' ) {
return $override;
}
// v3.1 by adding meta_remove filter, now this is sometimes called without the value element
// add the element as blank text
// this is necessary (vs just exiting the function) because otherwise if a field is left blank
// it won't get saved as such without the meta_remove filter
if (!array_key_exists('value', $a)) {
$a['value'] = null;
}
// if not a field for the custom table, just return
// what we got in and let CMB2 handle saving it.
global $mbdb_edit_book;
if ( in_custom_table( $a['field_id'] ) ) {
$mbdb_edit_book[$a['field_id']] = $a['value'];
return 'override';
} else {
return $override;
}
}
// set priority to 20 to ensure it runs after CMB2's hook
add_action('save_post', 'you_save_custom_table_function', 20);
function you_save_custom_table_function( $post_id ) {
if (!get_post_type() == 'your_post_type') {
return;
}
// save custom database fields to database
global $mbdb_edit_book;
// this translates post meta field ids to column names,
// sanitizes the data, and ultimately calls wpdb->update or insert
save_custom_post( $mbdb_edit_book, $post_id );
}
