Chopin's Prelude in D-flat major is also sometimes known as the "Raindrop Prelude". Like many classical pieces, the title also refers to the tonality: the music opens and closes in D-flat major....
None. There are 2 sharps, C# and F#
D Flat Major Scale has a relative minor key of B Flat Minor and has keys of: Bb-Eb-Ab-Db-Gb