Q&A Hero

Q: A(n) ____ is the attribute in the supertype entity that determines to which entity subtype each supertype occurrence is related.a. subtype discriminator b. inheritance discriminator c. specialization hierarchyd. entity supertype

Q: At the implementation level, the supertype and its subtype(s) depicted in the specialization hierarchy maintain a(n) ____ relationship.a. self-referencing b. 1:1 c. 1:Md. M:N

Q: One important inheritance characteristic is that all entity subtypes inherit their ____ key attribute from their supertype.a. primary b. natural c. foreignd. surrogate

Q: The property of ____ enables an entity subtype to inherit the attributes and relationships of the supertype.a. subtype discriminator b. inheritance c. specialization hierarchyd. entity supertype

Q: A specialization hierarchy can have ____ level(s) of supertype/subtype relationships.a. zerob. only one c. one or manyd. many

Q: Within a specialization hierarchy, every subtype can have ____ supertype(s) to which it is directly related.a. zero b. only one c. one or manyd. many

Q: The ____ depicts the arrangement of higher-level entity supertypes (parent entities) and lower-level entity subtypes (child entities).a. subtype discriminator b. inheritance c. specialization hierarchyd. entity supertype

Q: ____ is a generic entity type that is related to one or more entity subtypes.a. A subtype discriminatorb. Inheritance c. A specialization hierarchyd. An entity supertype

Q: The extended entity relationship model (EERM) is sometimes referred to as the ____.a. entity relationship model b. enhanced entity relationship model c. entity clustering relationship modeld. extended entity relationship diagram

Q: Some designs use redundant relationships as a way to simplify the design.

Q: 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.

Q: To model time-variant data, you must create a new entity in a M:N relationship with the original entity.

Q: An entity cluster is a "virtual" entity type used to represent multiple entities and relationships in the ERD.

Q: Generalization is based on grouping unique characteristics and relationships of the subtypes.

Q: Specialization is the top-down process of identifying lower-level, more specific entity subtypes from a higher-level entity supertype.

Q: The completeness constraint can be partial or total.

Q: Implementing non-overlapping subtypes requires the use of one discriminator attribute for each subtype.

Q: Overlapping subtypes are subtypes that contain a unique subset of the supertype entity set.

Q: Disjoint subtypes are subtypes that contain nonunique subsets of the supertype entity set.

Q: An entity supertype can have disjoint or overlapping entity subtypes.

Q: The property of subtype discriminator enables an entity supertype to inherit the attributes and relationships of the subtype.

Q: In specialization hierarchies with multiple levels of supertype/subtypes, a lower-level supertype inherits all of the attributes and relationships from all of its upper-level subtypes.

Q: Entity subtypes do not inherit the relationships in which the supertype entity participates.

Q: At the implementation level, the supertype and its subtype(s) depicted in the specialization hierarchy maintain a 1:1 relationship.

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

Q: Within a specialization hierarchy, a supertype can exist only within the context of a subtype.

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

Q: Entity supertypes and subtypes are organized in a specialization hierarchy.

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

Q: What is a ternary relationship? Provide some example business rules that specify the need for a ternary or higher-order relationship.

Q: What is a weak relationship? Provide an example.

Q: Explain multivalued attributes, and provide an example. How are multivalued attributes indicated in the Chen model? How are they indicated in the Crow's Foot model?

Q: Explain single-valued attributes and provide an example. Is an attribute that is single-valued always simple? Why or why not? Use an example to illustrate your point.

Q: Explain the difference between simple and composite attributes. Provide at least one example of each.

Q: ____________________ not only helps you stay on track during the design process, it also enables you and your coworkers to pick up the design thread when the time comes to modify the design.

Q: Identifying the attributes of the entities helps you better understand the ____________________ among entities.

Q: A(n) ____________________ process is based on repetition of processes and procedures.

Q: A relationship ____________________ indicates the number of entities or participants associated with a relationship.

Q: Failure to understand the distinction between mandatory and optional____________________ in relationships might yield designs in which awkward (and unnecessary) temporary rows (entity instances) must be created just to accommodate the creation of required entities.

Q: In Crow's Foot notation, an optional relationship between entities is shown by drawing a(n) ____________________ on the side of the optional entity.

Q: Participation is ____________________ if one entity occurrence does not requirea corresponding entity occurrence in a particular relationship.

Q: The Chen notation identifies the weak entity by using a double-walled entity ____________________.

Q: A weak entity must be ____________________-dependent.

Q: The Crow's Foot notation depicts the strong relationship with a(n) ____________________ line between the entities.

Q: A(n) ____________________ relationship is also known as an identifying relationship.

Q: Relationship strength depends on how the primary key of the related entity is formulated, while the relationship ____________________ depends on how the business rule is written.

Q: In the relationship "EMPLOYEE claims DEPENDENT" the DEPENDENT entity is ____________________ on the EMPLOYEE entity.

Q: When indicating cardinality, the first value represents the ____________________ number of associated entities.

Q: The relationship ____________________ is difficult to establish if you know only one side of the relationship.

Q: Storing ____________________ attributes requires constant maintenance.

Q: A(n) ____________________ attribute need not be physically stored within the database.

Q: Instead of storing a person's age, it is better to store the date of birth and use the difference between that value and the system date as a(n) ____________________ attribute.

Q: A person's social security number would be an example of a(n) ____________________ attribute.

Q: ____________________ are underlined in an ER diagram.

Q: A(n) ____________________ attributeis an attribute that must have a value.

Q: ____________________ are characteristics of entities.

Q: The ____________________ refers to a specific table row as an entity instance.

Q: The ERM forms the basis of a(n) ___________________________________.

Q: The Crow's Foot model is more ____________________-oriented than the Chen model.

Q: Complex ____ requirements may dictate data transformations, and they may expand the number of entities and attributes within the design.a. informationb. entity c. designd. processing

Q: If the focus is on data-retrieval speed, you might also be forced to include ____ attributes in the design, which would not ordinarily be done.a. multivalued b. composite c. weakd. derived

Q: The M:N relationship between STUDENT and CLASS must be divided into two 1:M relationships through the use of the ENROLL entity; the ENROLL entity is ____.a. weak b. strong c. optionald. mandatory

Q: If Tiny College had some departments that were classified as "research only," they would not offer courses; therefore, the COURSE entity would be ____ to the DEPARTMENT entity.a. existence-dependent b. independent c. weakd. optional

Q: The following step occurs first in the process of building an ERD: ____. a. Develop the initial ERD. b. Create a detailed narrative of the organization's description of operations. c. Identify the attributes and primary keys that adequately describe the entities. d. Identify the business rules based on the description of operations.

Q: The associative entity is also known as a ____ entity.a. unary b. weak c. strongd. composite

Q: A(n) ____ entity is composed of the primary keys of each of the entities to be connected.a. associative b. recursive c. unaryd. binary

Q: If an employee within an EMPLOYEE entity has a relationship with itself, that relationship is known as a ____ relationship.a. self b. self-referring c. loopingd. recursive

Q: ____ relationships are most common.a. Unary b. Binary c. Ternaryd. Higher-degree

Q: A ____ relationship exists when three entities are associated.a. unary b. binary c. ternaryd. weak

Q: A ____ relationship exists when two entities are associated.a. unary b. binary c. ternaryd. weak

Q: A ____ relationship exists when an association is maintained within a single entity.a. unary b. ternary c. binaryd. weak

Q: The Crow's foot symbol with two parallel lines indicates ____ cardinality.a. (0,N) b. (1,N) c. (1,1)d. (0,1)

Q: The existence of a(n) ____ relationship indicates that the minimum cardinality is at least 1 for the mandatory entity.a. mandatory b. optional c. multivaluedd. single-valued

Q: The term "____"is used to label any condition in which one or more optional relationships exist.a. participation b. optionality c. cardinalityd. connectivity

Q: A ____ entity has a primary key that is partially or totally derived from the parent entity in the relationship.a. strong b. weak c. businessd. relationship

Q: When the PK of one entity does not contain the PK of a related entity, the relationship is ____.a. missing b. weak c. strongd. neutral

Q: If an entity can exist apart from one or more related entities, it is said to be ____-independent.a. existence b. relationship c. businessd. weak

Q: An entity is said to be ____-dependent if it can exist in the database only when it is associated with another related entity occurrence.a. existence b. relationship c. businessd. weak

Q: Another word for existence-independent is ____.a. weak b. alone c. unaryd. strong

Q: In the ERD, cardinality is indicated using the ____ notation.a. (max, min) b. (min, max) c. [min ... max]d. {min|max}