Database Chapter 4
In crow's foot style E-R diagrams, a circle across the relationship line near an entity indicates: A) a minimum cardinality of zero. B) a minimum cardinality of one. C) a maximum cardinality of one. D) a maximum cardinality of many. E) Both B and C
A
A use case can be used to perform which of the following tasks? A) Transform the data model into the database design B) Validate the data model C) Fill the database with data D) Implement business rules E) Develop applications
B
Which of the following activities is not performed during the implementation phase of developing a database system? A) Filling the database with data B) Transforming the data model into a database design C) Writing application programs D) Creating forms E) Creating reports
B
Which of the following is not a stage in the development of a database system? A) Requirements analysis B) Validation C) Component design D) Implementation E) All of the above are stages in the development of a database system.
B
In the Entity-Relationship data model, all instances of an entity of a given type are grouped into: A) entity objects. B) class objects. C) entity classes. D) identifiers. E) entity attributes.
C
The representation of the content, relationships, and constraints of the data needed to support the system requirements is the: A) relation design. B) implementation. C) data model. D) data view. E) application program.
C
Whether or not an instance of one entity class must participate in a relationship with another entity class is indicated by the: A) degree. B) recursive cardinality. C) minimum cardinality. D) maximum cardinality. E) ordinality.
C
Which of the following is true about identifiers of entities? A) Identifiers must be unique. B) Identifiers are not normally used in a naming role. C) The value of an identifier may identify a set of entity instances. D) Identifiers may not be more than two attributes. E) An identifier in the E-R model is equivalent to a key in the relational model.
C
Which of the following would not be contained in a use case? A) Inputs provided to the system to perform a task B) A description of a task the user wants to perform C) A prototype of the system performing a given task D) Outputs generated by the system in performing a given task E) All of the above would be contained in a use case.
C
In crow's foot style E-R diagrams, a crow's foot mark on the relationship line near an entity indicates: A) a minimum cardinality of zero. B) a minimum cardinality of one. C) a maximum cardinality of one. D) a maximum cardinality of many. E) Both B and C
D
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) a strong entity relationship. B) an ID-dependent weak entity relationship. C) a non-ID-dependent weak entity relationship. D) a supertype / subtype relationship. E) a recursive entity relationship.
D
The number of entity classes involved in a relationship is known as the relationship's: A) maximum cardinality. B) minimum cardinality. C) ordinality. D) degree. E) class.
D
Which of the following is not a basic element of the E-R Model? A) Identifiers B) Entities C) Cardinalities D) Use cases E) Relationships
D
A dashed line between entities indicates: A) a unique identifier. B) a minimum cardinality of zero. C) a minimum cardinality of one. D) an identifying relationship. E) a nonidentifying relationship.
E
An ID-dependent entity is: A) a special type of weak entity. B) an entity in which the identifier of the entity includes the identifier of another entity. C) a strong entity. D) an entity with a maximum cardinality of one. E) Both A and B
E
In crow's foot style E-R diagrams, a hash mark across the relationship line near an entity indicates: A) a minimum cardinality of zero. B) a minimum cardinality of one. C) a maximum cardinality of one. D) a maximum cardinality of many. E) Both B and C
E
Which of the following is not a source for user requirements during the requirements analysis stage of developing a database system? A) Business rules B) User interviews C) Forms D) Use cases E) All of the above are sources for user requirements.
E
During the design phase of developing a database system, the users are asked about the need for changes to existing forms and reports (T/F).
False
During the implementation phase of developing a database system, the data model is transformed into a database design (T/F).
False
In crow's foot E-R notation, the crow's foot indicates a maximum cardinality of one (T/F).
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 (T/F).
False
One type of strong entity is the ID-dependent entity (T/F).
False
System requirements as documented by use cases, business rules, forms, reports, and queries are sufficient to design a database without using a formal data model (T/F).
False
The PRODUCT entity instance is a collection of all PRODUCT entity classes (T/F).
False
The number of entity classes involved in a relationship is the cardinality of the relationship (T/F).
False
There is usually only one instance of an entity in an entity class (T/F).
False
Unified Modeling Language (UML) has quickly replaced the E-R model as the most popular technique for creating data models (T/F).
False
A use case is a description of the way a user will employ the features and functions of the new system (T/F).
True
An entity class is described by the structure of the entities in that class (T/F).
True
An entity identifier can be either unique or nonunique (T/F).
True
In crow's foot E-R notation, a circle indicates a minimum cardinality of zero (T/F).
True
In crow's foot E-R notation, the hash mark indicated both a minimum cardinality of one and a maximum cardinality of one (T/F).
True
It is possible for an entity to have a relationship to itself (T/F).
True
Subtype entities may be either exclusive or inclusive (T/F).
True
The E-R Model assumes that all instances of a given entity class have the same attributes (T/F).
True
Use cases can be used to validate the data model, design, and implementation (T/F).
True
When developing a database system, the database is constructed during the implementation phase (T/F).
True
