Exam 2: Data Modeling

In a one-to-many binary relationship an occurrence of one entity type can be associated with many occurrences of the same entity type.

Each building on a university campus has several faculty offices. Each professor has one office. The relationship between campus buildings and professors is a _____ relationship.

A binary relationship is one in which each entity occurrence is associated with exactly two other entity occurrences.

A ternary relationship involves three different entity types.

Intersection data is associated with one of the two entities in a many-to-many relationship.

A ternary relationship allows an occurrence of one entity type to be associated with _____.

It is not necessary to have an associative entity describe a many-to-many binary relationship if there is not intersection data.

In a university setting, every professor reports to another professor who is the department chair. This is a _____ relationship.

A many-to-many binary relationship allows an occurrence of one entity type to be associated with _____.

A one-to-one unary relationship associates one occurrence of an entity type with one occurrence of another entity type.

In a university, the relationship between courses and their sections can best be described as a _____ relationship.

Intersection data describes the many-to-many relationship between two entities.

A binary relationship is a relationship between two entity types.

A university wants to keep track of which professor taught which subject to which student. This is a _____ relationship.

An associative entity is an alternate way of expressing a(n) _____.

A one-to-many unary relationship allows an occurrence of the entity type on the "one side" of the relationship to be associated with _____.

Draw an entity-relationship diagram that describes the following business environment. Grand Travel Airlines has to keep track of its flight and airplane history. A flight is uniquely identified by the combination of a flight number and a date. In addition, every flight has an actual departure time and an actual arrival time. Every passenger who has flown on Grand Travel has a unique passenger number plus their name, address, and telephone number. For a particular passenger who has taken a particular flight, the company wants to keep track of the fare that she paid for it and the date that she made the reservation for it. Clearly, a passenger may have taken many flights (he must have taken at least one to be in the database) and every flight has had many passengers on it. A pilot is identified by a unique pilot (or employee) number, a name, date of birth, and date of hire. A flight on a particular date has exactly one pilot. Each pilot has typically flown many flights but a pilot may be new to the company, is in training, and has not flown any flights, yet. Each airplane has a unique serial number, a model, manufacturer name, passenger capacity, and year built. A flight on a particular date used one airplane. Each airplane has flown on many flights and dates, but a new airplane may not have been used at all, yet. Grand Travel also wants to maintain data about its airplanes' maintenance history. A maintenance procedure has a unique procedure number, a procedure name, and the frequency with which it is to be performed on every airplane. A maintenance location has a unique location name, plus an address, telephone number, and manager. Grand Travel wants to keep track of which airplane had which maintenance procedure performed at which location. For each such event it wants to know the date of the event and the duration.

A many-to-many unary relationship allows an occurrence of one entity type to be associated with _____.

A one-to-many binary relationship allows an occurrence of the entity type on the "one side" of the relationship to be associated with _____.

Draw an entity-relationship diagram that describes the following business environment. Central Zoo wants to maintain information about its animals, the enclosures in which they live, and its zookeepers and the services they perform for the animals. In addition, Central Zoo has a program by which people can be sponsor of animals. Central Zoo wants to track its sponsors, their dependents, and associated data. Each animal has a unique animal number, species, name (Jumbo, Fred, etc.), gender, country of birth, and weight. Enclosures have a unique enclosure number, type (cage, fenced field, etc.), location, size, and date built. An animal can live in only one enclosure. An enclosure can have several animals in it or it can be currently empty. A zookeeper has a unique employee number, employee name, title, and year hired. Some zookeepers supervise other zookeepers. Every animal has been cared for by at least one and generally many zookeepers; each zookeeper has cared for at least one and generally many animals. Each time a zookeeper performs a specific, significant service for an animal the service type, date, and time are recorded. A sponsor sponsors at least one and possibly several animals. An animal may have several sponsors or none. A sponsor has a unique sponsor number, a name, address, and telephone number. For each animal that a particular sponsor sponsors, the zoo wants to track the annual sponsorship contribution and renewal date. In addition, Central Zoo wants to keep track of each sponsor's dependents, keeping their name, relationship to the sponsor, and date of birth. A sponsor may have several dependents or none. A dependent is associated with exactly one sponsor.