1) a recording studio needs help designing its database . The studio stores information about musicians and albums. Draw and ER diagram describing the studio’s database for each of the two scenarios described below. Assume that the only business rules that hold are those stated below, and that no additional business rules hold. Clearly mark all key and participation constraints.

(a) Each musician who records at the studio has a social security number (ssn) and a name, and no two musicians have the same ssn. Musicians form bands. A band is described by a unique name and has at least one musician as a member.

Bands record albums, which have a title and a year of production. Each album is recorded by exactly one band, and no two albums have the same title and the same production year. Each album is produced by exactly one musician. (Don’t worry about whether that musician is a member of the recording band.)

Albums are made up of songs, described by their titles. You may assume that, if the studio no longer wants to store information about an album, then it also does not store the songs belonging to that album. Naturally, each song belongs to exactly one album, and all songs on the same album have different title.

2) Each employee in an engineering company has at most one recognized skill, but a given skill may be possessed by several employees. An employee is able to operate a given machine-type (e.g., lathe, grinder) if he has one of several skills, but each skill is associated with the operation of only one machine type. Possession of a given skill (e.g., mechanic, electrician) allows an employee to maintain several machine-types, although maintenance of any given machine-type requires a specific skill (e.g., a lathe must be maintained by a mechanic).