documentclass[ngerman,twoside=false]{scrbook}
defmypagestyle{,mbox{---},}

RedeclareSectionCommands[
  tocraggedpagenumber,
  toclinefill={footnotesizemypagestyle},
  tocindent=0em,
  tocnumwidth=4em,
]{chapter,section,subsection,subsubsection,paragraph}

RedeclareSectionCommand[
   ,tocentryformat=largescshape%
   ,tocindent=0em
   ,tocnumwidth=4em
]{part}

RedeclareSectionCommand[%
    ,tocentryformat=textbf,%
]{chapter}
begin{document}
  tableofcontents
  part{part}
  chapter{chapter chapter}
  section{section section section}  section{section section section}  section{section section section}
  part{part}
  chapter{chapter chapter}
  section{section section section}  section{section section section}  section{section section section}
  setcounter{page}{100}
  part{part}
  chapter{chapter chapter}
  section{section section section}  section{section section section}  section{section section section}
end{document}