Identify the foreign keys in this schema. Explain how the entity and referential integrity rules apply to these relations.
What will be an ideal response?
For each relation, the primary key must not contain any nulls.
Room is related to Hotel through the attribute hotelNo. Therefore, the hotelNo in Room should
either be null or contain the number of an existing hotel in the Hotel relation. In this case study, it
would probably be unacceptable to have a hotelNo in Room with a null value.
Booking is related to Hotel through the attribute hotelNo. Therefore, the hotelNo in Booking
should either be null or contain the number of an existing hotel in the Hotel relation. However,
because hotelNo is also part of the primary key, a null value for this attribute would be
unacceptable. Similarly for guestNo. Booking is also related to Room through the attribute
roomNo.
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