CSIS304 chapter 4 – Flashcards
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The Crow's foot symbol with two vertical parallel lines indicates _____ cardinality.
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(1,1)
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A relationship is an association between _____.
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entities
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Knowing the minimum and maximum number of _____ occurrences is very helpful at the application software level.
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entity
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A weak entity has a primary key that is partially or totally derived from the parent entity in the relationship.
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True
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In Chen notation, there is no way to represent cardinality.
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False
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Referential integrity and participation are both bidirectional, meaning that they must be addressed in both directions along a relationship.
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False
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Connectivities and cardinalities are established by concise statements known as business rules.
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True
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A weak relationship exists if the primary key of the related entity contains at least one primary key component of the parent entity.
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False
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Software vendors have adopted the Chen representation because of its compact representation.
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False
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A _____ attribute can be further subdivided to yield additional attributes.
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composite
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If an employee within an EMPLOYEE entity has a relationship with itself, that relationship is known as a _____ relationship.
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recursive
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The Crow's Foot notation is less implementation-oriented than the Chen notation.
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False
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The _____ notation of entity-relationship modelling can be used for both conceptual and implementation modelling.
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UML
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Composite attributes make it easier to facilitate detailed queries.
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False
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When using the Crow's Foot notation, the associative entity is indicated by _____ relationship lines between the parents and the associative entity.
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solid
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A derived attribute is indicated in the Chen notation by a _____ that connects the attribute and an entity.
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dashed line
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The existence of a(n) _____ entity indicates that its minimum cardinality is zero.
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optional
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In organizations that generate large number of transactions, _____ are often a top priority in database design.
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high processing speeds
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Unary relationships are common in manufacturing industries.
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True
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Relationships between entities always operate in one direction.
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False
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The first step in building an entity-relationship diagram (ERD) is _____.
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creating a detailed narrative of the organization's description of operations
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In the Chen and Crow's Foot notations, an entity is represented with a rectangle containing the entity's name.
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True
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A _____ relationship exists when three entities are associated.
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ternary
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In a 1:M relationship, to avoid the possibility of referential integrity errors, the data of the "1" side must be loaded first.
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True
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_____ expresses the minimum and maximum number of entity occurrences associated with one occurrence of the related entity.
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Cardinality
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If Tiny College has some departments that are classified as "research only" and do not offer courses, the COURSE entity of the college database would be _____ the DEPARTMENT entity.
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optional to
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A _____ relationship exists when an association is maintained within a single entity.
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unary
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Complex _____ requirements may dictate data transformations, and they may expand the number of entities and attributes within the design.
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information
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The entity relationship model (ERM) is dependent on the database type.
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False
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A composite identifier is a primary key composed of more than one attribute.
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True
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An entity is said to be _____-dependent if it can exist in the database only when it is associated with another related entity occurrence.
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existence
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The Crow's Foot notation easily identifies multivalued attributes.
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False
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In implementation terms, an entity is existence-dependent if it has a mandatory primary key.
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False
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If an entity can exist apart from all of its related entities, then it is existence-independent, and it is referred to as a(n) _____ entity.
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strong
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Ideally, an entity identifier is composed of _____ attribute(s).
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one
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A _____ attribute is one that cannot be subdivided.
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simple
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The decision to store _____ attributes in database tables depends on the processing requirements and the constraints placed on a particular application.
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derived
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In the entity relationship model, a table row corresponds to an entity instance.
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True
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The existence of a mandatory relationship indicates that the minimum cardinality is 0 or 1 for the mandatory entity.
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False
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To simplify the conceptual design, most higher-order relationships are decomposed into appropriate equivalent _____ relationships whenever possible.
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binary
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The conceptual model can handle _____ relationships and multivalued attributes.
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M:N
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When the specific cardinalities are not included on the diagram in Crow's Foot notation, cardinality is implied by the use of _____.
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symbols
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An entity in the entity relationship model corresponds to a table in the relational environment.
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True
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In the entity relationship diagram (ERD), cardinality is indicated using the _____ notation, where max is the maximum number of associated entities and min represents the minimum number of associated entities.
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(min,max)
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A(n) _____ is the set of possible values for a given attribute.
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domain
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In the original Chen notation, each attribute is represented by an oval with the attribute name connected to an entity rectangle with a line.
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True
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To implement a small database, a database designer must know the "1" and the "M" sides of each relationship and whether the relationships are mandatory or optional.
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True
