WP_Debug not displaying anything

The constant to output errors to screen is actually

define( 'WP_DEBUG_DISPLAY', true );

WP_DEBUG_LOG would generate a debug.log in your wp-content directory, not in your site root.

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