We want to build an Entity-Relationship model for the database of a company which manages the concerts. A concert for musical works takes place in a hall at a given date. Several musicians play in a concert and everyone has a role. We also know the authors of a musical work by their last names and first names. Concert halls are located in different buildings, each one has an address in the form of a number and a street name and can have several concert halls. For each room, we know its capacity by counting the seats, all the seats being in the same category. Several musical works may be presented at each concert. Seat reservations are dated and are referenced by the phone numbers of people who made them. Each seat reservation is for a single concert. Give an Entity-relationship diagram of this application. Deduce the relational schema of the corresponding database