Programatically changing template of a page

Looking at the wp_postmeta table, you can see the page template is stored there.

Therefore, a simple call to update_post_meta (codex) should do the trick :

 update_post_meta( $post_id, '_wp_page_template', 'my_template.php' );

The filename and extension is necessary, as per my example.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)