CIS 464 3-2
True or False: A member of a subtype does NOT necessarily have to be a member of the supertype.
False
True or False: A subtype is a generic entity that has a relationship with one or more entities at a lower level.
False
True or False: Adapting a packaged data model from your DBMS vendor makes it difficult for the application to work with other applications from the same vendor.
False
True or False: Creating a data model from a packaged data model requires much more skill than creating one from scratch.
False
True or False: Data models of an existing database are harder for data modelers to read.
False
True or False: Generalization is a top-down process.
False
True or False: Packaged data models cause projects to take more time to build.
False
True or False: Regardless of the business situation, a member of the supertype is always a member of more than one subtype.
False
True or False: Subtypes at the lowest level of a hierarchy do not inherit attributes from their ancestors.
False
True or False: The disjoint rule specifies that if an entity instance of the supertype is a member of one subtype, it MUST simultaneously be a member of another subtype.
False
True or False: The total specialization rule states that an entity instance of a supertype is allowed not to belong to any subtype.
False
True or False: You will never need to map data in current databases to data in a packaged data model.
False
True or False: A completeness constraint may specify that each entity of the supertype must be a member of some subtype in the relationship.
True
True or False: A subtype can become a supertype if the subtype has other subtypes beneath it.
True
True or False: A universal data model is a generic or template data model that can be reused as a starting point for a data modeling project.
True
True or False: An entity cluster can have a relationship with another entity cluster much the same way that an entity can have a relationship with another entity.
True
True or False: An entity cluster should focus on some area of interest to some community of users, developers, or managers.
True
True or False: An entity instance of a subtype represents the same entity instance of the supertype.
True
True or False: Because a purchased data model is extensive, you begin by identifying the parts of the data model that apply to your data modeling situation
True
True or False: Entity clustering is a methodology for grouping one or more entity types and associated relationships into a single abstract entity type.
True
True or False: In a supertype/subtype hierarchy, attributes are assigned at the highest logical level that is possible in the hierarchy.
True
True or False: It is easier to share information across organizations if companies in the same industry use the same universal data model as the basis for their organizational databases.
True
True or False: Mapping existing data to new data in a packaged data model is useful for developing migration plans.
True
True or False: One of the major challenges in data modeling is to recognize and clearly represent entities that are almost the same.
True
True or False: Packaged data models are as flexible as possible, because all supertype/subtype relationships allow the total specialization and overlap rules.
True
True or False: Packaged data models are meant to be customized.
True
True or False: Packaged data models can be developed using proven components.
True
True or False: Specialization is the reverse of generalization.
True
True or False: Supertype/subtype relationships should not be used when the instances of a subtype participate in no relationships which are unique to that subtype.
True
True or False: The most important challenge of customizing a purchased data model is determining the business rules that will be established through the data model.
True
True or False: The overlap rule specifies that if an entity instance of the supertype is a member of one subtype, it can simultaneously be a member of two (or more) subtypes.
True
True or False: There are three separate discriminators in the following diagram (flip card) because of the overlap rule.
(scroll for answer) . . . . . . . . . . . . . . True
True or False: The following figure (flip card) is an example of total specialization.
(scroll for answer) . . . . . . . . . . . . . False
True or False: The following figure (flip card) is an example of the overlap rule.
(scroll for answer) . . . . . . . . . . . . False
True or False: The following diagram (flip card) is an example of a supertype/subtype hierarchy.
(scroll for answer) . . . . . . . . . . . . True
True or False: In the figure shown below (flip card), a rental unit can be both a house and an apartment.
(scroll for answer) . . . . . . . . . . . . false
True or False: In the figure shown below (flip card), a rental unit can be both an apartment and a house but must be at least one.
(scroll for answer) . . . . . . . . . . . . false
True or False: In the figure shown below (flip card), a rental unit has to be either a house or an apartment.
(scroll for answer) . . . . . . . . . . . True
True or False: In the figure shown below (flip card), there could be an instance of a rental unit that is neither an apartment nor a house.
(scroll for answer) . . . . . . . . . . . true
