CGS1540 study guide ch. 1-4 & 6

recursive

A business rule states that an employee may be supervised by another employee. This example of a(n) _____ relationship

records

A company with ten plants might have a PLANT file or a PLANT data set that contains ten ______.

True

A database represents some aspect of the real world called the universe of interest

Rectangles

A relationship can exist only between entities. Therefore, in a diagram a diamond cannot connect anything other than ______

diamond

A relationship type is shown as a ______

false

A requirement that specifies that a minimum of 100 employees must work in a plant can be reflected in the presentation layer ER diagram

business rules

A step-by-step analysis of the requirements specification will enable an analyst/modeler to extract specific conditions and procedures inherent in the universe of interest as _____.

Parent

A weak entity type can have another weak entity type as it's identifying ______

numeric

A(n) ________ data type is used when an attribute's value can consist of positive and negative numbers

object class

A(n) ________ is a generalization of related object types that have shared properties

relationships

An entity type can participate in one or more _____ with other entity types.

True

An entity type related to itself is termed a recursive relationship type

mutually exclusive relationship types

An exclusive arc represents ______

underlined with solid line

Attribute that serves as unique identifier of a base entity type is _____

mandatory

Attributes that are ______ cannot have missing values.

Optional

Attributes that need not be assigned a value for each entity are referred to as _______ attributes.

Deletion

Data management involves four actions: data creation, data retrieval, data modification or updating, and data ______

False

Data modeling is no longer a necessary part of the database design process due to the recent emergence of new database design technologies

Physical

Database design follows a life cycle that includes three tiers: conceptual data modeling, logical data modeling, and ______ data modeling

parent in a parent-child (binary) relationship (PCR)

Deletion constraints apply to possible actions when the _____ is deleted.

instance diagram

Diagrammatic representation of the relationship among entity types in terms of relationship instances among the instances of the participant entity types is called a(n) ______.

True

ER modeling grammar does not permit modeling a relationship between an entity type and an attribute of an entity type

edges

In the notational scheme used in this chapter, a relationship is shown through the use of ______ that connect the relationship type to the participating entity types.

False

One objective of database systems is to establish program-data dependence

False

One way to arrive at the first cut of an ER diagram is to begin by listing all discernible data elements from the narrative, treat them all as relationships, and then attempt to group these relationships based on apparent commonalities among them

partial

Since the combination of the dependent name and the dependents relationship to the employee is unique for a given employee, the composite attribute dependent, a composite attribute, consisting of the atomic attributes Dname and related_how, appears as a(n) _________ key

design-specific

What is one of the two basic layers of the ER model?

restrict

When a parent entity in a relationship is deleted, if all child entities related to this parent in this relationship should also be deleted, the _______ rule applies

existence dependency

____ of an entity type in a relationship type implies mandatory participation of all entities in the entity set of the said entity type in that relationship

Business rules

_____ are an organized conglomeration of user-specified restrictions on the organization's activities (business processes) that must be reflected in the database and/or database applications.

data redundancy

_____ in file-processing systems not only creates maintenance inefficiencies but also leads to the problem of not knowing which is the current , correct data

logical data

_______ independence enables a user view to be immune to changes in the other user views

true

a composite or molecular attribute can be meaningfully subdivided into smaller subparts with independent meaning

underlined with a dotted line

a partial key is _____ in the ER diagram

double diamond

a relationship type that connects a weak entity type to its identifying parent entity type is shown as a ______

false

a weak entity type is not always also existent dependent on the corresponding identifying relationship type

attribute

a(n) _____ is shown by a circle with the name written adjacent to the circle

derived

an attribute can be either a stored attribute or a _____ attribute

True

an entity type can and often does have multiple unique identifier can be an atomic or composite attribute

false

an entity type where the entities have independent existence is referred to as a weak entity type

true

an explicit relationship between attributes of an entity type independent of the entity type is not permitted in the ER modeling grammar

true

as a high-level diagrammatic portrayal of the application domain, an ER diagram is not capable of capturing some of the finer business rules that are part of the data requirements

true

categorization is represented similarly to specialization except that the circle symbol that signifies the categorization relationship contains the letter U to indicate that the membership in the subclass set results from the union of multiple superclasses

true

despite today's sophisticated information technologies, there are still only two primary approaches for accessing data

business rules

during the conceptual design, the focus should be on capturing the user

index

for direct access, the records in a file can be stored serially and be organized either randomly or using an external _____

Unique

identifiers appear underlined in the ER diagram

total

if in order to exist, every entity must participate in the relationship, then participation of the entity type in that relationship type is ______ participation

false

in a 1:n relationship type, attributes of the relationship can alternatively be shown only as attributes of the parent entity type in the relationship and not of the child entity type

true

in general it may not be efficient to replace a partial category with a generalization/specialization construct

true

in general, integrity constraints are considered to be part of the schema in that they are declared along with the structural design of the data model

base

in order to contrast it from a weak entity type, the entity type is often referred to as a ____ entity type.

composite

in the ER diagram, a(n) ______ attribute Name of the EMPLOYEE entity type is shown as consisting of the atomic attributes Fname, Minit, Lname, and Name_tag

synthesis

in the ______ approach to ER modeling, the modeler will list all discernable data elements from the narrative, treat them all as attributes, and then attempt to group these attributes based on apparent commonalities among them

physical

once a logical schema has been developed, the process moves on to the ______ design tier

false

one objective of database systems is to establish program-data dependence

true

physical design involves using the tools of a particular DBMS product to create the database and to design and develop applications that address the high-level requirements of the universe of interest

True

sometimes a category may not have a unique identifier

crow's foot

the ___ notation was originally introduced by Everest (1986) for the knowledgeware software

access routines

the _____ handle database access at run time by passing requests to the file manger of the operating system to retrieve data from the physical files of the database

presentation

the _____ layer ER diagram is a surface-level expression of the application domain

ER model

the basic units of a(n) ______ are entity type, entity class, attribute, uni

cascade

the business rule if a project is deleted , all assignments of employees to that project must be deleted implies a _______ rule

false

the conceptual data model describes the structure of the data to be stored in the database and specifies how and where it will be physically stored and the methods used to retrieve it

true

the input source for the conceptual modeling phase is the business rules culled out from the requirements specification supplied by the user community

A

the letter _____ inside a circle is used to represent aggregation of subclasses

true

the maximum cardinality indicates the maximum number of relationship instances in which an entity participates

completeness

the participation of the superclass in the specialization is referred to as the ____ constraint

logical schema

the product of the logical design activity is the _____

false

the properties of the unique identifier may not vary across a category

True

the source of integrity constraints are the business rules that emerge from the user requirements specification for a database application system.

true

the unique identifier of the entity type can be used to identify an entity distinctly from other entities in the entity set

false

the uniqueness constraint is imposed on an attribute to ensure that its observed value is not outside the defined domain

on some unique identifier

to facilitate sequential access, all records in a file must be stored ordered ____

true

total and partial participation are also commonly referred to as mandatory and optional participation

False

unique identifiers are identified in ER-modeling by circled attributes

design specific

what is one the two basic layers of the ER model?

diagram and a list of semantic integrity constraints

what is the output of presentation layer ER modeling?

semantic

you have a _____ error when there is an incorrect imposition of a business rule implicit in the requirements specification

False

Data does not necessarily need to be organized in order to be accessed from a database

False

Consider the following business rule: Bearcat Incorporated offers CREDIT UNION facilities as a service to its employees and to their dependents. BCU accounts are identified by a unique account ID, composed of an account number and an account type. For each account, the account balance is recorded. it is reasonable to conclude that account ID is most likely to be modeled as an entity type

True

File-processing systems are dependent upon a programmer who either has to write or modify program code to meet these information requirements from isolated data.

o

If a business rule states a football player can also be a basketball player and/or baseball player, and football player, basketball player, and baseball player are all specializations of a common superclass, the disjointness constraint should have a value of _____

rectangular box

In ER diagrams a ______ is used to represent an entity type

False

In ER diagrams, empty circles represent mandatory attributes while dark circles signify optional attributes

false

In a diagram there can be entities (e11, e12, ....) of E1 not related to an entity of E2. This is known as total participation of E1 in relationship R

data sharing

In a file-processing system, data is separated and isolated, and ownership of data is compartmentalized, resulting in limited ______.

rectangular box

In all notations for entity relationship diagrams, an entity type is expressed by a(n) ______.

False

In the conceptual world an object class is a generalization of different entity types that have shared attributes

Consistency

In the context of every relationship type in an ER model, the deletion of an entity from the parent entity type required specific action either in the parent entity set or in the child entity set in order to maintain _______ of the relationships in the database

true

In the notational scheme used in the chapter for the presentation layer ER model, both the cardinality ratio and the participation constraint are expressed via a "look across" approach.

False

In the notational scheme used in this chapter, a derived attribute is represented by a gray circle

False

The DML compiler makes use of the data dictionary to look up the required data component structures and relationships

analysis

The _______ approach begins with a search for things that can be labeled by singular nouns (a person, place, thing, or concept) which are modeled as entity types of the ER diagram

domain

The presentation layer ER diagram is a surface-level expression of the application _____

end-user communication tool

The presentation layer ER model is the most useful as a(n) _____

True

The set of all relationship instances involving pilots and flights is defined as a relationship set

On some unique identifier

To facilitate sequential access, all records in a file must be stored ordered _______