Show info to author only

Just compare display names:

$currentuser = get_currentuserinfo();

if ( get_the_author() == $currentuser->displayname ) {
     // current user is the post author; do something
}

The get_the_author() function returns displayname, which should be able to be compared against the displayname parameter that is a part of the $currentuser object.

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