Chapter 4

________ constrain data values and the processing of the database.

Business rules

In crow's foot style E-R diagrams, a hash mark across the relationship line near an entity indicates ________.

1. a minimum cardinality of zero 2. a maximum cardinality of one

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.

Entity instance

An entity instance is a representation of a particular entity within the entity class. The entity instance is described by the values of the attributes of the entity. An entity class, then, is a collection containing many entity instances.

One type of strong entity is the ID-dependent entity.

FALSE

Which of the following is not a source for user requirements during the requirements analysis stage of developing a database system?

Referential integrity constraints

An entity identifier can be either unique or nonunique.

TRUE

Changing aspects of a source document is much more difficult than changing the actual database, once constructed.

TRUE

________ are descriptions of the ways users will employ the features and functions of the new information system.

Use cases

The Microsoft Access report editor is a(n) ________.

banded report editor

Relationships with the degree two are often called ________ relationships.

binary

Microsoft Access database files can be easily ________ to create multiple copies of a database.

copied

In the Entity-Relationship data model, all instances of an entity of a given type are grouped into ________.

entity classes

A(n) ________ is a working demonstration of selected portions of the future system.

prototype

In crow's foot style E-R diagrams, an entity class is represented by a(n) ________.

rectangle

Maximum cardinality

the maximum number of entities that can be involved in a relationship. Maximum cardinality is typically represented as being either 1:1 (one-to-one), 1:N (one-to-many), N:1 (many-to-one), or M:N (many-to-many).

An ID-dependent entity is ________.

1. a special type of weak entity 2. an entity in which the identifier of the entity includes the identifier of another entity

The number of entity classes involved in a relationship is known as the relationship's ________.

class

Identifiers of an entity that are composed of two or more attributes are called ________ identifiers.

composite

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 is known to be true?

A single instance of ENTITY B may be related to many instances of ENTITY A.

Entity class

An entity class is the collection of all entities of a given type. The entity class is described by the structure of the entities in that class.

Entity identifiers

An entity identifier is an attribute or group of attributes that is used to name or identify instances of an entity class. An entity identifier is more of a logical concept. It is simply an attribute that the users think of as distinguishing between entity instances in their environment. Also, entity identifiers may be unique or nonunique. If an entity identifier is unique, it will identify a single instance of the entity class. If the identifier is nonunique, it will identify a set of instances of the entity class.

A PRODUCT entity instance is the collection of all PRODUCT entity classes.

FALSE

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 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

Recursive relationships can be represented as 1:N or N:M, but not 1:1.

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: Which is known to be true?

Many instances of ENTITY A may be related to one instance of ENTITY B.

Because of its forms and reports wizards, ________ can be used to build a prototype database for many different other operational DBMS.

Microsoft Access

________ can be used to build prototype databases.

Microsoft Access

Which of the following is not a basic element of the E-R Model?

Relationships

A use case is a description of the way a user will employ the features and functions of the new system.

TRUE

An entity cannot be both weak and strong.

TRUE

An entity class is described by the structure of the entities in that class.

TRUE

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.

TRUE

In a traditional E-R diagram, the relationship is symbolized by a diagram.

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

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

Business rules role in database design

The business rules are typically documented with the database design so that they can be enforced through procedural logic and application programs.

How is minimum cardinality expressed in crow's foot E-R diagrams?

The crow's foot E-R diagram notation uses a circle to indicate a minimum cardinality of zero (or "optional") and a hash mark to indicate a minimum cardinality of one (or "mandatory"). Each symbol is placed on the relationship line just beyond the symbol indicating maximum cardinality.

How is maximum cardinality expressed in crow's foot E-R diagrams?

The crow's foot E-R diagram notation uses a hash mark to indicate a maximum cardinality of one and a crow's foot to indicate a maximum cardinality of many. Each symbol is placed immediately next to the rectangle symbolizing an entity. These symbols are combined in various forms to signify 1:1, 1:N and N:M relationships.

Database design

The database design is created from the data model to include tables, relationships, constraints, data types, column properties, and descriptions of primary and foreign keys. The database design is a component design of how database technology can accomplish the support of the system requirements depicted in the data model.

Minimum cardinality

The minimum number of instances of one entity that may be associated with each instance of another entity.

Which of the following is true about identifiers of entities?

The value of an identifier may identify a set of entity instances.

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 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

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 uses ________ form and report editors.

banded

The Microsoft Access form editor is a(n) ________.

banded form editor

The ________ is a representation of the content, relationships, and constraints of the data needed to support the system requirements.

data model

The representation of the content, relationships, and constraints of the data needed to support the system requirements is the ________.

data model

Weak entity

includes any entity that relies on another entity for its existence in the database.

Recursive relationships occur when an entity has a relationship with ________.

itself

Whether or not an instance of one entity class must participate in a relationship with another entity class is indicated by the ________.

minimum cardinality

When an entity class has a relationship with itself, it is called a(n) ________ relationship

recursive

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

An entity that must logically depend on another entity is called a(n) ________ entity

weak

Microsoft Access ________ allow easy mock-ups of forms and reports for prototyping

wizards

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

A dashed line between entities indicates ________.

a nonidentifying relationship