Bcis 4620 mid term

Which of the following is an example of entity clustering for a doctor?

Surgeon, therapist, pediatrician

Let's assume that college football has many divisions. With this, each division has many players, and each division has many teams. Given these "incomplete" business rules. What type of relationship is division in with the players and the team?

division is in a 1:m relationship with team and players

What is the general rule that is used when using entity clusters?

to avoid the display of attributes

The purpose of an entity _____ is to simplify an entity-relationship diagram (ERD) and thus enhance its readability.

cluster

One important inheritance characteristic is that all entity subtypes inherit their _____ key attribute from their supertype.

primary

_________ is the bottom-up process of identifying a higher-level, more generic entity supertype from lower-level entity subtypes.

Generalization

What is the benefit of the entity clustering?

avoid the display of attributes to eliminate complications that result when the inheritance rules change

The entity supertype contains the common characteristics and the entity subtypes contain the unique characteristics of each entity subtype

True

Which of the answers below is familiar to end users and forms part of their day-to-day business vocabulary?

A natural key

What type of keys are useful as identifiers of weak entities, where the weak entity has a strong identifier relationship with the parent entity?

composite key

What occurs when you have one entity in two 1:M relationships to other entities, which then produces an association among the other entities that is not expressed in the model?

fan trap

What is the best data type for a primary key?

numeric

In the enhanced-entity-relationship, what is the collection of entities in this set classified as?

class

When there is a discriminator of a weak entity how is the set specified?

using a dashed line

What type of identifier relationship ensures that the dependent entity can exist only when it is related to the parent entity?

strong

One important inheritance characteristic is that all entity subtypes inherit their _____key attribute from their supertype.

primary

Which of the following is an example of a foreign key?

Its value can be deleted from the child table.

The purpose of an entity _____ is to simplify an entity-relationship diagram (ERD)and thus enhance its readability.

cluster

The _______ characteristic of a primary key states that the primary key must uniquely identify each entity instance, must be able to guarantee unique values, and must not contain nulls.

unique values

Which of the following can be null?

foreign key

The __ is used to develop an initial ERD that contains a few entities.

Data modeler

Using a data modeling point of view, what data refers to data whose values changeover time and for which there must be kept a history of the data changes?

time variant

Without the _________, the primary key inheritance rule changes.

Key attributes

What type of line represents a partial completeness constraint

single horizontal line under the circle

An entity cluster is considered "virtual" or "_____" in the sense that it is not actually an entity in the final ERD.

abstract

____ relationships occur when there are multiple relationship paths between related entities.

Redundant

The function of the primary key is to describe an entity.

False

The surrogate key has __ meaning in the user's environment.

No meaning

What type of key has the practical advantage in that it has no intrinsic meaning?

Surrogate

The "_____" characteristic of a primary key states that the primary key should not have embedded semantic meaning.

nonintelligent

According to the "preferably single-attribute" characteristic of a primary key, the primary key:

should have the minimum number of attributes possible.

How many entities can be represented in an entity cluster?

Multiple

The relationships depicted within the specialization hierarchy are sometimes described in terms of "is-a" relationships.

True

Implementing overlapping subtypes requires the use of one discriminator attribute for each subtype.

True

A design trap occurs when a relationship is improperly or incompletely identified and is therefore represented in a way that is not consistent with the real world.

True

Which of the following is a specialization hierarchy overlapping constraint scenario in case of partial completeness?

Supertype has optional subtypes.

Which of the answers below is not the most important characteristic of an entity?

A foreign key

If we are creating subtypes for a car dealership. Why would an accountant be a subtype of an employee?

because it is identifiable with employees and has unique attributes

Your boss needs you to show a specialization hierarchy that can reflect the relation between EMPLOYEES and its subtypes. What type of relationship do you need to show your boss?

1:1

A large entity relationship model (ERM) diagram was presented to management by the relationships between each entity was hard to understand visually, especially with dashed lines. If using the Crow's Foot model to depict the relationships, what other actions could be done to the ERM to make it more understandable in terms of number of occurrences in the related entities?

Notate the cardinality next to each table

A weak relationship exists if the primary key of the related entity contains at least one primary key component of the parent entity.

False

If a database designer had to determine the amount of revisions required to plan the completion of the database design, how many iterations would most likely take to account for all operational requirements in the database?

Many

In an ERD that say DOCTOR writes PRESCRIPTION, a PATIENT receives a PRESCRIPTION, and a DRUG appears in a PRESCRIPTION, it is mostly portraying what type of relationship degree?

Ternary

Attribute examples such as STU_LNAME, STU_FNAME, and ROM_NUMBER would apply to one entity.

False

If a college had professors who are not always assigned a class, but created classes would require one professor, then what is the relationship of the PROFESSOR table to the CLASS table?

Mandatory

The marketing team is not able to distinguish customers in a specific city because the CUSTOMER table is too compact. The table's attributes must be broken down to make the customer's city a groupable query. Which of the following attributes should be simplified to improve queries for the CUSTOMER table?

ADDRESS

When a company reorganizes its executive branch so executives can manage more than one division, the employee database will need to update its relationship between the EXECUTIVE and DIVISION tables to which of the following?

1:1 to 1:M

Connectivities and cardinalities are established by concise statements known as business rules.

True

If a college with a department called Research must also offer courses to its students, just like all other departments that offer courses, then what type of relationship would a COURSE have to a DEPARTMENT in an entity relationship diagram (ERD)?

Mandatory

If TEAM and PLAYER have a mandatory relationship where PLAYER has a cardinality expressed as (6,12), which of the following is true about the TEAM object?

Team must have a minimum of 6 players

When designing an ERD segment where a DEPARTMENT must have one or more PROFESSORs assigned to it, but the DEPARTMENT can only be chaired by one PROFESSOR, how would the "chairs" relationship be visualized on the DEPARTMENT table?

Optional