database quiz 4 – Flashcards
Unlock all answers in this set
Unlock answersquestion
The concept of relationship strength is based on how the ___________ of a related entity is defined
answer
primary key- The concept of relationship strength is based on how the primary key of a related entity is defined.
question
When indicating cardinality, the first value represents the__________ number of associated entities.
answer
minimum- When indicating cardinality, the first value represents the minimum number of associated entities. The second value indicates the maximum
question
The entity relationship diagram (ERD) represents the _____ database as viewed by the end user. A condensed B physical C logical D conceptual
answer
D conceptual
question
A _____ attribute is one that cannot be subdivided. A multivalued B composite C simple D single-valued
answer
C simple
question
Unary relationships are common in manufacturing industries. True or False
answer
True- Because of the Marriage attributes
question
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.
answer
participation- Failure to understand the distinction between mandatory and optional participation 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. Participation is OPTIONAL if one entity occurrence does not require a corresponding entity occurrence in a particular relationship.
question
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 A strong B weak C alone D unary
answer
A strong- If an entity can exist apart from all of its related entities, then it is existence-independent, and it is referred to as a strong entity
question
The Crow's Foot notation depicts the strong relationship with a(n) _________ line between the entities.
answer
Solid- The Crow's Foot notation depicts the strong relationship with a solid line between the entities. weak relationship is with a dashed line
question
Complex _________ requirements may dictate data transformations, and they may expand the number of entities and attributes within the design. A processing B information C entity D design
answer
B information- Complex information requirements may dictate data transformations, and they may expand the number of entities and attributes within the design.
question
Referential integrity and participation are both bidirectional, meaning that they must be addressed in both directions along a relationship. True False
answer
False- Referential integrity deals with the correspondence of values in the foreign key with values in the related primary key. Referential integrity is not bidirectional, and therefore answers only one question: i.e. Must every employee spouse be a valid employee?
question
In the entity relationship model, a table row corresponds to an entity instance True or False
answer
True- In the entity relationship model, a table row corresponds to an entity instance
question
Composite attributes make it easier to facilitate detailed queries. True or False
answer
False Composite attribute that can be further subdivided to yield additional attributes To facilitate detailed queries, it is wise to change composite attributes into a series of simple attributes. Lesson: The Relational Model of Data Objective: IMPORTANT: The Entity Relationship Model (ERM)
question
The entity relationship model (ERM) is dependent on the database type. True or False
answer
False The ERM uses ERDs to represent the conceptual database as viewed by the end user. The ERM's main components are entities, relationships, and attributes. The ERD includes connectivity and cardinality notations, and can also show relationship strength, relationship participation (optional or mandatory), and degree of relationship (such as unary, binary, or ternary).
question
_________________ are underlined in an ER diagram.
answer
Identifiers- Identifiers are underlined in an ER diagram.
question
In the Chen and Crow's Foot notations, an entity is represented with a rectangle containing the entity's name True or False
answer
True In the Chen and Crow's Foot notations, an entity is represented with a rectangle containing the entity's name
question
Ideally, an entity identifier is composed of _____ attribute(s). A six B two C one D three
answer
C one
question
A(n)________ attribute is an attribute that must have a value.
answer
required- A required attribute is an attribute that must have a value.
question
___________not only helps database designers to stay on track during the design process, it also enables them to pick up the design thread when the time comes to modify the design.
answer
Documentation- Documentation not only helps database designers to stay on track during the design process, it also enables them to pick up the design thread when the time comes to modify the design.
question
____________ are characteristics of entities.
answer
Attributes - Attributes are characteristics of entities.
question
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 business D data
answer
A existence An entity is said to be EXISTENCE -dependent if it can exist in the database only when it is associated with another related entity occurrence. A Weak entity must be existence dependent.
question
A(n)_____________attribute need not be physically stored within the database.
answer
Derived- A derived attribute need not be physically stored within the database.
question
A(n)_____________ process is based on repetition of processes and procedures.
answer
iterative- An iterative process is based on repetition of processes and procedures.
question
Knowing the minimum and maximum number of ___________ occurrences is very helpful at the application software level. A attribute B object C entity D data
answer
C entity Knowing the minimum and maximum number of entity occurrences is very helpful at the application software level
question
The Chen notation identifies a weak entity by using a double-walled entity___________
answer
Rectangle- The Chen notation identifies a weak entity by using a double-walled entity rectangle.
question
A(n)_____________ relationship is also known as an identifying relationship.
answer
strong- A strong relationship is also known as an identifying relationship.
question
The __________ notation of entity-relationship modelling can be used for both conceptual and implementation modelling. A Crow's Foot B Chen C UML D Bachman
answer
C UML
question
The first step in building an entity-relationship diagram (ERD) is ___________ . A identifying the attributes and primary keys that adequately describe the entities B creating a detailed narrative of the organization's description of operations C developing the initial ERD D identifying the business rules based on the description of operations
answer
B creating a detailed narrative of the organization's description of operations
question
A relationship _____________ is difficult to establish if only one side of the relationship is known
answer
Classification- Explanation: A relationship classification is difficult to establish if only one side of the relationship is known.
question
A derived attribute is indicated in the Chen notation by a _____ that connects the attribute and an entity. A double dashed line B dashed line C single line D double line
answer
B dashed line
question
To simplify the conceptual design, most higher-order relationships are decomposed into appropriate equivalent _____ relationships whenever possible. A binary B unary C weak D strong
answer
A binary
question
The decision to store _____ attributes in database tables depends on the processing requirements and the constraints placed on a particular application. A multivalued B derived C single-valued D composite
answer
B derived
question
A relationship _________________ indicates the number of entities or participants associated with a relationship.
answer
degree A relationship degree indicates the number of entities or participants associated with a relationship.
question
In implementation terms, an entity is existence-dependent if it has a mandatory primary key. True or False
answer
False- A property of an entity whose existence depends on one or more other entities. In such an environment, the existence-independent table must be created and loaded first because the existence-dependent key cannot reference a table that does not yet exist
question
Connectivities and cardinalities are established by concise statements known as business rules. True or False
answer
True
question
A composite identifier is a primary key composed of more than one attribute. True or False
answer
True In ER modeling, a key composed of more than one attribute
question
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. True or False
answer
True
question
The Crow's Foot notation is less implementation oriented than the Chen notation. True or False
answer
False
question
The Crow's Foot notation easily identifies multivalued attributes. True/False
answer
False- The Crow's Foot notation does not identify multivalued attributes. Lesson: The Relational Model of Data Objective: IMPORTANT: The Entity Relationship Model (ERM)
question
When the specific cardinalities are not included on the diagram in Crow's Foot notation, cardinality is implied by the use of ___________. A images B attributes C symbols D tables
answer
C symbols
