Remote database data manipulation

From your description and code, it seems you want to transfer user data from a local WordPress database to a remote database. Your approach is almost correct, but there are a few issues that could be causing the blank page or preventing the code from working. Key Points to Check and Suggestions:

1. Check for PHP Errors:
   Blank pages often indicate a PHP error. Even though you have enabled debugging, PHP errors might not be outputted correctly. You can add the following code at the top of your file to ensure all errors are displayed:

   ini_set('display_errors', 1);
   ini_set('display_startup_errors', 1);
   error_reporting(E_ALL);

2. Syntax Error in Your Code:
   There is a mistake in this line:

   $external_users = $other_db->'users';

It should be:

   $external_users = $other_db->prefix . 'users'; // Assuming 'users' table has a prefix

or simply:

   $external_users = 'users';

The -> operator cannot be used to directly access a string. You need to correct that.

3. Inserting Data into the Remote Database:
   The wpdb::insert() method should be called on the correct $other_db instance, not the local $wpdb instance. Your code should look like this:

   $other_db->insert(
       $external_users,
       array(
           'username' => $user->user_login,
           'hash'     => $user->user_pass,
           'email'    => $user->user_email,
       )
   );

4. Database Table Structure:
   Ensure that the remote database has the exact table structure for the users table and that the column names match. For example, if the column names are user_login, user_pass, and user_email, use those exact names.
5. Debugging:
   You can add logging to see if your code runs up to a certain point. For example:

   error_log('Reached this point before inserting data.');

Check the debug.log file in the wp-content directory for the logged messages.

6. Database Connection Validation:
   You’re currently checking the connection like this:

   if (!$other_db) {
       echo $wpdb->show_errors();
   }

However, $other_db is an object, so this check will always pass. Instead, validate the connection using the last_error property:

   if ( $other_db->last_error ) {
       error_log('Database connection error: ' . $other_db->last_error);
   } else {
       echo 'Connected successfully';
   }

7. Avoid Hardcoding the Table Name:
   WordPress tables usually have prefixes (like wp_). Use the $wpdb->prefix property to handle this dynamically if needed.

Final Revised Code Example:

require __DIR__ . '/wp-load.php';
define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true );

ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

global $wpdb;

$other_db = new wpdb($other_db_user, $other_db_password, $other_db_name, $other_db_host);

if ( $other_db->last_error ) {
    error_log('Database connection error: ' . $other_db->last_error);
} else {
    echo 'Connected successfully';
}

$user = get_userdata($user_id);

if ( $user ) {
    $external_users = 'users'; // Adjust the table name as needed

    $result = $other_db->insert(
        $external_users,
        array(
            'username' => $user->user_login,
            'hash'     => $user->user_pass,
            'email'    => $user->user_email,
        )
    );

    if ( $result === false ) {
        error_log('Insert error: ' . $other_db->last_error);
    } else {
        echo 'Data inserted successfully.';
    }
} else {
    error_log('User not found.');
}

Additional Tips:

• Make sure the remote database user has the correct permissions to insert data.
• Ensure that the remote table structure and column names match the data you’re inserting.
• Check the debug.log file and PHP error output for clues if the issue persists.

This should resolve your issues and help in successfully inserting data into the remote database.

Thank you. Will try the updated code when i arrive back home.

So to make it clear…

This code will take the data i need from the local database and put it on the remote one ? Or just into the remote one ? Because i do need it to get as normal on the local database also.

The entire process i want to do is to just retrive some of the data from the local database into the remote one. You might call it as a small backup. (using cron eventually)

Tried the code and it seems it makes some confusing. He thinks the remote db connection details to use on the local database and gives me access denied on my local database and undefined $user_id because cannot access the local database to pull out the data.

That’s why i’ve tried to pull the local data, then make another wpdb instance for the remote database and then insert the data pulled from local to remote one.