Save all posts automatically and execute function

I don’t think you want to do it on post save, you’re going to run out of resources fast that way.

I would write a script that does these things:

1. custom db query to get all dates, with post_ids as the keys.
2. verify you got good data
3. remove all terms from the age taxonomy
4. loop over the dates, do your calculation, and use wp_create_term() to create the proper terms with values and post_id relationships.

This is going to run WAY faster than actually saving all your posts.

As for cron, I don’t personally like WP-Cron, it’s not super reliable. In your script do a test for a GET var, something like this:

if ( ! empty( $_GET['get_ages'] && $_GET['get_ages'] == true ) {
  // DO STUFF
}

Then use any other cron to do an http request to your homepage with ?get_ages=true at the end. Run it once at midnight or something. You can use the command line cron on your server if you want, or from your own machine (unreliable), or there are web services which will let you pay $1/mo or something to run a command on cron.

• This reply was modified 2 years, 2 months ago by Topher.

The taxonomy query is going to be WAY faster than a custom field query with math in it. Plus as a term you can do all sorts of other interesting things like make data maps of age groups, without every hitting the posts table.

First use a tool like phpMyAdmin to look at the postmeta table and find your custom fields. Is the date stored in plain text like 2022-10-01 or is serialized somehow? Plain text is preferred, but we could work with serialized.

Read about $wpdb: https://developer.wordpress.org/reference/classes/wpdb/

That makes it easy to send a custom query. Something like this:

$birth_dates = $wpdb->get_results(
    "SELECT post_id, meta_value FROM {$wpdb->postmeta} WHERE <code>meta_key</code> = 'YOURKEYNAME'"
);

where YOURKEYNAME is whatever you called your birthdate field.

I don’t know for sure what the format will be coming back from that, but to be sure then you can do something like this:

$birth_dates_array = [];
foreach ( $birth_dates as $birth_date ) {
    $birth_dates_array[ $birth_date->post_id ] = $birth_date->meta_value;
    // it might be this instead:
    // $birth_dates_array[ $birth_date['post_id'] ] = $birth_date['meta_value'];
}

then you’ll have an array that looks like this:

[
1,'2022-10-01',
2,'1971-07-17'
]

then it’s a plain array. Use foreach to loop over it and use wp_set_post_terms (I misspoke about wp_create_term above) to connect posts to terms.

• This reply was modified 2 years, 2 months ago by Topher.

The custom table shouldn’t matter, you can just adjust the query accordingly. If you look stuff up in phpMyAdmin it’ll show you the query it used.

The array I showed has post_ids as keys and dates as values. So you’d do something like

foreach ( $birth_dates_array as $post_id => #term ) {
  wp_set_post_terms( $post_id, $term, 'WhateverYourTaxonomyIs' );
}

Rock on!