returning error on “show table data”

Hi
Getting the following error when clicking on the “Show Table Data” button:

Fatal error: Uncaught Error: Call to undefined function mysql_connect() in /home/***/public_html/wp-content/plugins/database-to-excel/DatabaseToExcel.php:109 Stack trace: #0 /home/***/public_html/wp-includes/class-wp-hook.php(298): DatabasetoExcel_html_page('') #1 /home/***/public_html/wp-includes/class-wp-hook.php(323): WP_Hook->apply_filters('', Array) #2 /home/***/public_html/wp-includes/plugin.php(453): WP_Hook->do_action(Array) #3 /home/***/public_html/wp-admin/admin.php(222): do_action('toplevel_page_D...') #4 {main} thrown in /home/***/public_html/wp-content/plugins/database-to-excel/DatabaseToExcel.php on line 109