In which TV series is Diane Chambers a main character?

In which TV series is Thomas Magnum a main character? Who played Michael Knight in 'Knight Rider'? Who played Sam Malone in 'Cheers'? Who played Diane Chambers in 'Cheers'? Who played Norm Peterson in 'Cheers'? In which TV series is Norm Peterson a main character? Who played Cliff Clavin in 'Cheers'? In which TV series is Cliff Clavin a main character?