Using the relational schema given, suppose that S1 is a fore…

Using the relational schema given, suppose that S1 is a foreign key referring to A1. Which of the following statements must be true?      R1                                                                                    R2  

Given the following schema, Pet (petId: integer, petType: st…

Given the following schema, Pet (petId: integer, petType: string, petName: string) Cat (petId: integer (FK), furColor: string) Dog (petId: integer (FK), furColor: string) Bird (petId: integer (FK), canFly: boolean)   Which expression can be used to create a list of animals that are either a cat or a dog?

Given the following schema, Pet (petId: integer, petType: st…

Given the following schema, Pet (petId: integer, petType: string, petName: String, favoriteFood: String) Cat (petId: integer (FK), furColor: string) Dog (petId: integer (FK), furColor: string) Bird (petId: integer (FK), canFly: boolean)   Which relational algebra expression is going to produce a list of distinct bird names for the birds who can fly?