Calling mysql_query() on another database, assumes WordPress using that database

Question

I'm attempting to import some data from a legacy site into WordPress. First step is terms for taxonomy event_category. Here is my approach:

$link = mysql_connect(
    'localhost',
    'blah',
    'blah'
);

// connect to old database
$dkpl_db = mysql_select_db('dkpldump', $link);

$event_categories = mysql_query('SELECT * FROM calendar_cats');
while($event_category = mysql_fetch_assoc($event_categories)){
    //create term!
    $term = wp_insert_term(
        $event_category['categoryId'],
        'event_category',
        array(
            'slug' => $event_category['categoryName']
        )
    );
    var_dump($term);
}

In my var_dump I'm getting following error:

WP_Error Object
(
    [errors] => Array
    (
        [db_insert_error] => Array
        (
            [0] => Could not insert term into the database
        )
    )
    [error_data] => Array
    (
        [db_insert_error] => Table 'dkpldump.wp_terms' doesn\'t exist
    )
)   

The problem is dkpldump is the database I'm trying to read from, not the database WordPress is installed on (dkpl). So why is it trying to write to dkpldump database and how can I fix it?

Answer 1

Use a new instance of wpdb to connect and read from the other database:

$mydb = new wpdb('blah','blah','dkpldump','localhost');
$event_categories = $mydb->get_results("SELECT * FROM calendar_cats");
foreach( $event_categories as $event_category ){
    //create term!
    $term = wp_insert_term(
        $event_category->categoryId,
        'event_category',
        array(
            'slug' => $event_category->categoryName
        )
    );
}