hostname in linux prompt manipulation

HOSTROLE=db-server-1
case $(whoami) in
    root)
        STARTCOLOUR='\[\e[31m\]';
        ENDCOLOR="\[\e[m\]"
        PS1="${STARTCOLOUR}[\u@${HOSTROLE} \w]# $ENDCOLOR";
        ;;
   oracle)
        STARTCOLOUR='\[\033[02;32m\]';
        ENDCOLOR="\[\e[m\]"
        PS1="${STARTCOLOUR}[\u@${HOSTROLE} \w]$ $ENDCOLOR";
        ;;
    *)
        STARTCOLOUR='\[\e[0m\]';
        ENDCOLOR="\[\e[m\]"
        PS1="${STARTCOLOUR}[\u@${HOSTROLE} \w]$ $ENDCOLOR";
        ;;
esac