Chapter 4 Data Base
A PRODUCT entity instance is the collection of all PRODUCT entity classes.
A PRODUCT entity instance is the collection of all PRODUCT entity classes.
In crow's foot style E-R diagrams, a crow's foot mark on the relationship line near an entity indicates ___
A maximum cardinality of many
In crow's foot style E-R diagrams, a circle across the relationship line near an entity indicates ____
A minimum cardinality of zero
Which of the following would not be contained in a use case?
A prototype of the system performing a given task
Given only the following excerpt of an E-R model: Which of the following is known to be true?
A single instance of ENTITY B may be related to many instances of ENTITY A
In crow's foot style E-R diagrams, a single entity together with a related set of entities that each contain specific sets of attributes related to the single entity represent __
A supertype / subtype relationship
Microsoft Access is a good tool for creating mock-ups of forms and reports because ___
Access wizards make it easy to create the forms and reports
Which of the following is not a source for user requirements during the requirements analysis stage of developing a database system?
All of the above are sources for user requirements
A nonidentifying relationship exists between an ID-dependent entity and its parent.
False
During the design phase of developing a database system, the users are asked about the need for changes to existing forms and reports.
False
During the implementation phase of developing a database system, the data model is transformed into a database design.
False
In a 1:1 relationship, a single entity instance of one type is related to a single entity instance of the same or another type.
False
In a traditional E-R diagram, the relationship is symbolized by a diagram.
False
In crow's foot E-R notation, the crow's foot indicates a maximum cardinality of one.
False
Maximum cardinality indicates whether or not an instance of one entity class must be related to at least one instance of another entity class.
False
Microsoft Access is only used to prototype databases where Microsoft Access itself will be the final DBMS.
False
One type of strong entity is the ID-dependent entity.
False
System requirements as documented by use cases, business rules, forms, reports, and queries are sufficient to design the database without using a formal data model.
False
The number of entity classes involved in a relationship is the cardinality of the relationship.
False
There is usually only one instance of an entity in an entity class.
False
Unified Modeling Language (UML) has quickly replaced the E-R Model as the most popular technique for creating data models.
False
Given only the following excerpt of an E-R model: graphic(Chapter 4:4-44to46.jpg) Which of the following is known to be true?
IDK
Given only the following excerpt of an E-R model: graphic(Chapter 4:4-44to46.jpg) If one instance of ENTITY B must be related to one and only one instance of ENTITY A, and one instance of ENTITY A may be related to many instances of ENTITY B, which of the following should be written on the end of the relationship line next to ENTITY B in the figure above?
Many instances of ENTITY A may be related to one instance of ENTITY B
Which of the following is true about identifiers of entities?
The value of an identifier may identify a set of entity instances
Microsoft Access can be used to build a prototype database, which allows users ________.
To validate the data model by demonstrating the consequences of data modeling decisions
Which of the following activities is not performed during the implementation phase of developing a database system?
Transforming the data model into a database design
A use case is a description of the way a user will employ the features and functions of the new system.
True
An entity class is described by the structure of the entities in that class.
True
An entity identifier can be either unique or nonunique.
True
In crow's foot E-R notation, a circle indicates a minimum cardinality of zero.
True
In crow's foot E-R notation, the hash mark indicates both a minimum cardinality of one and a maximum cardinality of one.
True
It is possible for an entity to have a relationship to itself.
True
Microsoft Access can be used to build a prototype database, which allows users to validate the data model by demonstrating the consequences of data modeling decisions.
True
Microsoft Access database files can be easily copied to create multiple copies of a database.
True
Microsoft Access uses banded form and report editors.
True
Microsoft Access wizards allow easy mock-ups of forms and reports for prototyping.
True
One or more entities can be associated together in relationships.
True
Recursive relationships can be represented as 1:N or N:M, but not 1:1.
True
Subtype entities may be either exclusive or inclusive.
True
The E-R Model assumes that all instances of a given entity class have the same attributes.
True
The subtype symbol is a circle with a line under it.
True
Use cases can be used to validate the data model, design, and implementation.
True
When developing a database system, the database is constructed during the implementation phase.
True
An entity cannot be both weak and strong.
True IDKKK
Which of the following is not a basic element of the E-R Model?
Use Cases
A use case can be used to perform which of the following tasks?
Validate the data model
Which of the following is not a stage in the development of a database system?
Validation
An ID-dependent entity is
___Both A & B_____. A special type of weak entity // an entity in which the identifier of the entity includes the identifier
In crow's foot style E-R diagrams, a hash mark across the relationship line near an entity indicates ___________
___Both B & C_____. A minimum cardinality of one // a maximum cardinality of one
Whether or not an instance of one entity class must participate in a relationship with another entity class is indicated by the
____minimum cardinality____.
The number of entity classes involved in a relationship is known as the relationship's
___degree_____.
A dashed line between entities indicates
a nonidentifying relationship
The Microsoft Access form editor is a(n) _________
banded form editor
The Microsoft Access report editor is a(n)
banded report editor
The representation of the content, relationships, and constraints of the data needed to support the system requirements is the ___
data model
In the Entity-Relationship data model, all instances of an entity of a given type are grouped into ______
entity classes
