Using these schema:

Songs (title, year, length, genre, studioName, producerC#)

Singers (songTitle, songYear, singerName )

SongSinger (name, address, gender, birthdate)

SongExec (name, cert#, address, networth)

Studio (name, address, presC#)

Express the following queries using Tuple Relational Calculus:

1.Find the titles of songs that have been used for two or more songs.

2.Find names of singers who sing in only songs made by Sony.

3.Find the Studio names, and names of studio presidents of studios which have Selena Gomez singing in every song the studio produces.