Chapter 06

Chapter 6 Data Modeling page 1Multiple Choice:A data model is a:

The mathematical model of formulas and logic used in a systemThe abstract creating of an ideal system transformationThe model that is produced by extreme programmingThe expanded, thoroughly balanced and normalized use case for a systemA formal way of representing the data that are used and created by a business system

Ans: eResponse: see IntroductionDifficulty: easy

A data model can __________:

Illustrate return-on-investment, break-even point, and economic feasibilityRepresent actions or processes that occur in the to-be systemBe used as a logical data model in analysis and as a physical data model in designOnly be used in BPR situationsOnly be used with JAD sessions

Ans: cResponse: see IntroductionDifficulty: easy

Which of the following is NOT illustrated by a data model?

PeoplePlacesThingsActionsNouns

Ans: dResponse: see IntroductionDifficulty: easy

Which of the following software packages does NOT provide data modeling capabilities?

ERwin Visual BasicOracle DesignerVisible Analyst WorkbenchVisio

And: bResponse: see IntroductionDifficulty: easy

ERwin, a CASE tool with data modeling features, was created by:

OracleMicrosoftPlatinum TechnologySun SystemsUnited Technologies

Ans: cResponse: see IntroductionDifficulty: medium

Which is NOT true about using Visible Analyst Workbench?

It can be used with many different databasesIt integrates the data model with other parts of the projectIt is a full-service CASE toolData modeling is one of many capabilitiesIt can generate Java code when the data modeling is done

Ans: eResponse: see IntroductionDifficulty: medium

ERD is an acronym for:

Enterprise Relationship DiagrammingEntity Relationship DiagrammingElectronic Repository DiagrammingEnhanced Relationship DiagrammingEntity Repository Design

Ans: bResponse: see IntroductionDifficulty: easy

Entity relationship diagramming (ERD) is a graphical drawing technique developed by:

Cole and WestonThomas BartonPeter ChenAlan DennisMartin and Chang

Ans: cResponse: see IntroductionDifficulty: hard

An entity relationship diagram (ERD):

Is a use-case diagram enhanced graphically to show data and process modelingIs a high-level CASE diagram of data modeling used in business systemsIs an illustration of external data flows to and from a business systemsIs a picture that shows the information that is created, stored and used by a business systemIs a graphical display of the processes in a business system

Ans: dResponse: see The Entity Relationship DiagramDifficulty: easy

An analyst can read an ERD to:

Discover the individual pieces of information in a system and how they are organized and related to each otherFind what processes use what dataDetermine the cardinality of processes in a system and if the modality of process is 1:M; 1:1; or M:NEvaluate data structure hierarchies as to processing anomalies in a business systemDiscover how the people, places and things in a business system are generated, moved, transformed and stored

Ans: aResponse: see The Entity Relationship DiagramDifficulty: hard

On an ERD _________________:

Processes are listed alphabetically with relationship connections drawn between processesData elements are listed alphabetically with a cross listing to the processes that manipulate themData elements are described as singular (1:1); plurals (1:N); or didactic (M:N)Data elements are grouped in a hierarchical structure that is uniquely identified by numberData elements are listed together and place inside boxes called entities.

Ans: eResponse: see The Entity Relationship DiagramDifficulty: hard

Lines on an ERD diagram indicate:

Hierarchies between processesRelationships among the dataPlurality of data itemsUniqueness of data itemsPrimary keys

Ans: bResponse: see The Entity Relationship DiagramDifficulty: medium

Which of the following is NOT true about ERDs?

Special symbols are added to show high-level business rulesThe diagrams are drawn in a sequential order from top to bottomSimilar kinds of information are listed together in entitiesERDs are data modeling techniquesLines are drawn to show relationships among the data

Ans: bResponse: see The Entity Relationship DiagramDifficulty: medium

Which is NOT an element of an Entity Relationship Diagram?

CardinalityModalityAttributeRelationshipData stores

Ans: eResponse: see Elements of an Entity Relationship DiagramDifficulty: easy

An entity:

Is the association between two related processesHas cardinality (1:1, 1:N, or M:N)Shows if it can be null or no nullIs a person, place or thingIs described with a verb phrase

Ans: dResponse: see Elements of an Entity Relationship DiagramDifficulty: easy

An attribute:

Is some type of information that is captured about an entityIs the basic building block for a data modelIs the association between entitiesIs the identification of parent and child entities Is drawn as a line between processes

Ans: aResponse: see Elements of an Entity Relationship DiagramDifficulty: easy

Which would NOT likely be an attribute of an entity called Student?

AgeStudent identification numberClass room numberHome phoneGender

Ans: cResponse: see Elements of an Entity Relationship DiagramDifficulty: medium

Which would NOT likely be an entity on a car insurance ERD?

CustomerPolicyAgentZip codeCar

Ans: dResponse: see Elements of an Entity Relationship DiagramDifficulty: medium

You have entities of ITEM, SOLD-ITEM, SALE and PAYMENT. Which most likely is NOT a relationship?

SALE is paid by PAYMENTPAYMENT pays for ITEMITEM is included in SOLD-ITEMSALE involves SOLD-ITEMPAYMENT pays for SALE

Ans: bResponse: see Elements of an Entity Relationship DiagramDifficulty: easy

Modality refers to:

Relationships of one-to-one; one-to-many; or many-to-manyWhether a child entity can exist with or without a related instance in the parent entityThe hierarchical structure that was developed in process models applied to data modelsThe number of attributes generated by an entityWhether the entity has a unique identifier (aka primary key) or a concatenated identifier (aka composite key)

Ans: bResponse: see Elements of an Entity Relationship DiagramDifficulty: hard

Jack is developing an ERD for a small dental practice office patient record system. The dental practice has three dentists, six hygienists, and many patients. A patient is always assigned to the same dentist for all appointments. In particular, he is working on the relationship between dentists and patients. Should it be:

1 to 1, with a modality of null1 to many with a modality of not nullMany to many with a modality of nullMany to many with a modality of not null1 to many with a modality of null

Ans: bResponse: see Elements of an Entity Relationship DiagramDifficulty: hard especially due to the assumptions you have to make about dentists & patients

CASE tools have a(n) __________________ where information about entities, attributes and relationships on the ERD are stored.

Information spaceData storeMeta fileData flowData dictionary

Ans: eResponse: The Data Dictionary and MetadataDifficulty: medium

Information in the data dictionary is called: _______________

MetadataCached informationCompiled dataData repositoryFile silo

Ans: aResponse: The Data Dictionary and MetadataDifficulty: medium

In the IDEF1X ERD notation, an entity is drawn as:

A diamond with the entity name in the middleA circle with the upper part of the circle with the entity nameA rectangle with the identifier written above (outside) the rectangleA rectangle with the identifier written in a darker color inside at the top of the rectangleA rectangle with the identifier written at the top of the rectangle with an asterisk

Ans: dResponse: see Elements of an Entity Relationship DiagramDifficulty: medium

Mike is drawing an ERD diagram. He has a one-to-many relationship. To identify the end of the relationship for the main relationship, Mike should draw:

An ovalA crows footThe letter MAn infinity symbol A diamond

Ans: bResponse: See Elements of an Entity Relationship DiagramDifficulty: easy

Entity Relationship Diagrams show relationships between entities that are _____.

Outputs from JAD sessions Consistent with the ACM guidelinesIn line with the business rules and processingDefined by the project sponsorExtensions of the process models

Ans: cResponse: See IntroductionDifficulty: hard

The three major parts of an ERD diagram are:

Process, data flow, data storeAttribute, modularity, cardinalityRelationship, data flow, entityRelationship, attribute, entityProcess, entity and relationship

Ans: dResponse: See Elements of Entity Relationship DiagramsDifficulty: easy

The basic building block of a data model is the:

EntityRelationshipAttributeCardinalityModality

Ans: aResponse: see Elements of Entity Relationship DiagramsDifficuly: easy

Which would most likely NOT be an entity on an ERD?

StudentProfessorClassPracticeEnroll

Ans: eResponse: See Elements of Entity Relationship DiagramsDifficulty: easy

What is true about creating an entity relationship diagram?

There will be at most seven entitiesThere will be at most seven relationshipsIf you identify more than seven entities, analyze and combine until you have seven or lessIt is an iterative processEntities will have at most seven attributes

Ans: dResponse: see Creating an Entity Relationship DiagramDifficulty: easy

In creating ERDs, which would most likely NOT be a source for entities?

Use casesLevel 0 DFD diagramsExternal entitiesData flowsCost / benefit reports

Ans: eResponse: see Creating an Entity Relationship DiagramDifficulty: medium

In adding attributes to an ERD, which of the following might NOT be a good resource for attributes?

From the CASE toolData flows from DFDsRequirements documentsThe system proposal documentThrough interviews (what users need for reports and processing)

Ans: dResponse: see Creating an Entity Relationship DiagramDifficulty: medium

The last step in creating basic ERDs is to:

Identify relationshipsDefine attributes and assign identifiersRecognize entitiesTest them with usersCompile them with Java

Ans: aResponse: see Creating an Entity Relationship DiagramDifficulty: medium

Sanjay is identifying relationships as he draws ERDs. He will need to:

Determine originality and functionalityInclude cardinality and crows feetAdd modality and functionalityDetermine modality and cardinalityInclude 1:1, 1:N and M:N relationships


Ting-You is creating an ERD diagram. She knows that it is a(n) _____________

Well defined processSequential processProcess defined by five stepsIterative processUser defined process


Anthony is working on the cardinality of doctors and patients in a large urban hospital. With the large number of doctors with varying specialties and patients that may have more than one aliment, he thinks the relationship might be noted as:

1 to 11 to 21 to manyMany to manyMany to 1


Omar has a model with 85 entities. He can:

Compress these into at most seven entity grouping unitsGroup these into related subject areasStop he has all entities definedSort the entities alphabeticallyCo-validate the entities with the level 2 DFD diagrams

Ans: bResponse: see Validating an ERDDifficulty: medium

The first step to building an Entity Relationship Diagram is to _____

Identify data flows from the level 0 DFD diagramdraw the relationships between the entitiesidentify the attributes for each entityidentify the entities identify the processes, data flows and data stores

Ans: dResponse: see Creating Entity Relationship DiagramsDifficulty: easy

When normalizing data models, if you take attributes that have multiple values for a single instance of an entity and create separate entities for those attributes you are moving from:

O normal form to 1st normal form (1NF)1st normal form (1NF) to 2nd normal form (2NF)2nd normal form (2NF) to 3rd normal form (3NF)Generalized normal form (GNF) to fully normalized form (FNF)Dependent normal form (DNF) to Independent normal form (INF)

Ans: aResponse: see Appendix 6A: normalizing the data modelDifficulty: medium

Independent entities are:

When a child requires attributes from the parentWhen there is only one entity for a data process modelWhen an entity can exist without the help of another entityWhere the entity identifier is also the primary keyWhen a entity comes from an external source (aka external entity)

Ans: cResponse: see Advanced SyntaxDifficulty: medium

A(n) _____ entity is an entity at the 1 end of a relationship or an entity with an identifier that describes only the entity.

dependentincompleteindependent intersectionnon-identifying

Ans: cResponse: See Advanced Syntax / Independent EntityDifficulty: medium

A(n) _____ entity cannot exist without the presence of another entity and is normally on the many end of a relationship or has an identifier that is based on another entitys attribute.independent incompletedependentvariable non-complying

Ans: cResponse: Advanced Syntax / Dependent EntityDifficulty: medium

The two methods to validate that an ERD is well formed are _____.

Balancing with process models and following design guidelines created by ChenNormalization and balancing with process modelsRenaming theoryBalancing with process models and renaming theoryNormalization and following design guidelines created by Chen

Ans: bResponse: See Validating the ERDDifficulty: medium

What are the rules covering the layout of ERD components?

Items that are related must be grouped into subject areasItems that are not related must be drawn on the bottom of the page They must be placed in alphabetical orderThey must be placed in numerical orderThere are no rules

Ans: eResponse: see Validating the ERDDifficulty: medium

Andrew, an analyst for PaxMedia Inc, has just learned that the business rules for a system he has been working on have changed. This means that _____.

Nothing once the ERD data models have been drawn, they are frozen for the systemAndrew will be reassigned to a different project that is in its beginning stagesThe ERD components will have to be changedThe ERD data model will have to be put on hold while new DFD diagrams are createdThe project will have to be scrapped and restarted

Ans: cResponse: See Validating the ERDDifficulty: medium

A logical data model that does not lead to repeating fields and that the data models leads to tables containing fields that are dependent on the whole identifier is in _____ normal form.

balancedfirstprimarysecond third

Ans: dResponse: See Appendix 6A Normalizing the Data ModelDifficulty: medium

When the analyst is evaluating a data model to ensure that all fields in a record depend fully on the entire primary key, which step of normalization is being performed?

base normal formfirst normal formsecond normal form third normal formcannot tell from the above information

Ans: cResponse: See Appendix 6A Normalizing the Data ModelDifficulty: medium

If the logical data model does not contain attributes that have repeating values it is in _____.

base normal formfirst normal form non-normal formsecond normal formthird normal form

Ans: bResponse: See Appendix 6A Normalizing the Data ModelDifficulty: medium

If the logical data model contains attribute values that depend on an attribute that is not the identifier, then it is in _____.

base normal formfirst normal formnon-normal formsecond normal formthird normal form

Ans: dResponse: See Appendix 6A Normalizing the Data ModelDifficulty: medium it is still in 2NF until the dependency noted above is removed

Balance occurs between DFDs and ERDs when the data stores _____

Are uniquely namedHave only one input and one output flowAre named the same as the relationships on the ERDCan be compared to ERD data flows and attributes on the ERD are included in data stores on the DFDCan be equated to entities on the ERD and when entities are referred to by data stores on the DFD

Ans: eResponse: See Normalization - BalancingDifficulty: medium

TRUE / FALSE QuestionsData models can be either logical or physical.

Ans: TrueResponse: see IntroductionDifficulty: easy

During the analysis phase, analysts create programming models to represent how the business system will operate.

Ans: FalseResponse: see IntroductionDifficulty: medium

A data model is a formal way of representing the data that are used and created by a business system.


The data that are used and created by a business system are illustrated by a process model.


Project teams generally use either Gantt or PERT charts to draw data models.


Project teams can use packages like ERwin or Oracle Designer or Visible Analyst Workbench to draw data models.


Logical data models are most commonly drawn with the Data Flow Diagram technique.


ERD is an acronym for Enterprise Reliability Diagrams.


One of the most commonly used techniques for data modeling is ERDs.

Ans: TrueResponse: see IntroductionDifficulty: medium

ERDs are drawn in several levels: Context ERD diagrams; Level 0 ERD diagrams; Level 1 ERD diagrams.


ERDs and DFDs are two techniques for data modeling.


ERDs and DFDs are two techniques for process modeling.


A textbook-provided example of a full-service CASE tool is Visible Analyst Workbench.


An ERD is a picture that shows how data and information is processed and transformed by a business system.

Ans: FalseResponse: see The Entity Relationship DiagramDifficulty: hard

A graphical illustration that shows the information that is created, stored and used by a business system would be an ERD.

Ans: TrueResponse: see The Entity Relationship DiagramDifficulty: easy

An illustration of the transformation of data into business value is an ERD.

Ans: FalseResponse: see The Entity Relationship DiagramDifficulty: medium

An analyst can read an ERD to discover the individual pieces of information in a system and how they are organized and related to each other.

Ans: TrueResponse: see The Entity Relationship DiagramDifficulty: easy

On an ERD, similar kinds of information are listed together and placed inside boxes called data containers.

Ans: FalseResponse: see The Entity Relationship DiagramDifficulty: medium

An entity is the basic building block for a data model.

Ans: TrueResponse: see Elements of an Entity Relationship DiagramDifficulty: easy

An entity is described by an action verb.

Ans: FalseResponse: see Elements of an Entity Relationship DiagramDifficulty: easy

Entities are further designed with attributes.


In an entity called STUDENT, you might find attributes of Student-ID, Last-Name, First-Name and cell-phone.


In an entity called STUDENT, you might find attributes of PROFESSOR-ID, Last-Name, First-Name and CLASSROOM.


Relationships are some type of information that is captured about entities.


Relationships are associations between entities.


Relationships are drawn with lines showing cardinality and plurality.

Ans: FalseResponse: see Elements of an Entity Relationship DiagramDifficulty: hard

ERDs can be quite complex and might have hundreds or thousands of entities.

Ans: TrueResponse: see Creating an Entity Relationship DiagramDifficulty: easy

The three steps in creating an ERD are: (1) identify the entities; (2) identify the processes; (3) identify the relationships

Ans: FalseResponse: see Creating an entity relationship diagramDifficulty: medium

Metadata is data about data.

Ans: TrueResponse: see The Data Dictionary and MetadataDifficulty: easy

CASE tools have data repositories.

Ans: FalseResponse: see The Data Dictionary and MetadataDifficulty: easy

In defining the data characteristics of Universal Product Codes, we might describe them as twelve characters made up of digits numeric only.

Ans: TrueResponse: see The Data Dictionary and MetadataDifficulty: medium

In defining LAST-NAME in the data dictionary, we might describe it as a character field having from 1 to 15 alphabetic characters.

Ans: FalseResponse: see The Data Dictionary and Metadata you will also need special characters like DAngelo or OBrienDifficulty: hard

One of the first places to start developing Entity Relationship Diagrams is by looking at the level 0 process models (DFD) and the use cases for data flows and data stores.

Ans: TrueResponse: see Creating an Entity Relationship DiagramDifficulty: medium

Looking at external entities can be helpful with creating entities.

Ans: TrueResponse: see Creating an Entity Relationship DiagramDifficulty: medium

Data modeling is an iterative process.

Ans: TrueResponse: see Creating an Entity Relationship DiagramDifficulty: easy

Most novice analysts understand quickly how to create ERDs.

Ans: FalseResponse: see Creating an Entity Relationship DiagramDifficulty: medium

Fortunately for novice analysts, there are fairly straight-forward rules and guidelines for creating ERDs.

Ans: FalseResponse: see Creating an Entity Relationship DiagramDifficulty: medium

The authors suggest that creating ERDs is pretty tough to do.

Ans: TrueResponse: see Validating an ERDDifficulty: easy

Michele has an entity called client and an entity called customer and an entity called shopper. All three names seem to refer to the same data in the business system. It is acceptable to use different names for an entity as it helps clarify the purpose of the entity.

Ans: FalseResponse: see Validating an ERDDifficulty: easy

Following carefully prepared and numbered use cases and DFDs, Chang has named his entities ITEM-1, ITEM-2, ITEM-3, etc. Because of the documentation, this is acceptable and recommended.

Ans: FalseResponse: see Validating an ERDDifficulty: easy

If an ERD gets too complex, it can be broken down into related subject areas.

Ans: TrueResponse: see Validating ERDDifficulty: easy

When validating ERDs you should balance ERD entities with the data flows and data stores from the DFD process diagrams.

Ans: TrueResponse: see NormalizationDifficulty: easy

When depicting the inter-realationship between process and data models it can be useful to refer to the CRUDE matrix (create, relate, update, define, edit).

Ans: FalseResponse: see NormalizationDifficulty: hard

The processes of creating process models, data models and using CASE tools are interrelated.

Ans: TrueResponse: see NormalizationDifficulty: easy

CRUD stands for create, read, update and delete and can be used to verify DFDs and ERDs.

Ans: TrueResponse: see NormalizationDifficulty: medium

Normalizing data models is a five step process: not-normalized; create first normal form (1NF); create second normal form (2NF); create third normal form (3NF); create fourth normal form (4NF) and finally create the fully normalized form (5NF).

Ans: FalseResponse: see Appendix 6A: Normalizing the data modelDifficulty: easy

Essays:

What are the three primary components of an ERD diagram?

Ans: Entity, attributes and relationshipsResponse: see Creating an Entity Relationship DiagramDifficulty: easy

You have an entity called STUDENT. What attributes might you have?

Ans: answers will vary, most likely most (or all) of the following:Student-idnumber (primary key); Lastname; firstname; birthdate; social security number; home address; home phone; SAT (ACT) scores; credits completed; courses taken; advisor; major; minor; GPA; local address; local phone; cell/mobile phone; gender; financial aid information (or link to a financial aid entity); etc.Response: see Creating an Entity Relationship DiagramDifficulty: medium

You have a student registration system (simplified) with three entities: Student, Professor, and Class. Assume standard attributes for the three entities. What might be the relationships, cardinality and modality between the three?

Ans: answers will vary; but something like:Professor teach classes (probably 1:M); a class is taught by 1 professor; students take classes (1:M); it might be possible to have a class with no students (so modality might be null) such as an advanced nuclear physics class taught at 5:00 a.m. ; it might be possible that a professor isnt teaching this semester (on sabbatical or doing research projects) so modality of null; could a student not be taking any classes? If so that could also have a modality of null (might be doing an internship that is not registered with the campus; might be on a study-abroad trip that isnt for credit and is not registered for; might have dropped out for the semester, etc.); professors have many students and student have many professors (M:N); and again if a professor is on sabbatical or doing research may not have students and if a student is not enrolled, he/she may not have any professors.Response: Creating an entity relationship diagramDifficulty: hard mainly due to the number of assumptions which must be made to make a correct diagram

In the sample data for the STUDENT entity, there are repeating values for class and semester attributes. For example Adam Murphy took CIS 370 section 2 in fall 2008; Brenda Olson took CIS 370 section 2 in fall 2008; Jing Zhang took CIS 370 section 2 in fall 2008; etc. What is the process to modify this entity so that there are no attributes with multiple values?

Ans: This is to put the entity into First Normal Form (1NF). Generally you will create a new entity Courses-Taken where each course each semester each section is placed and a relationship will be drawn between the entities. For this example, one entry in the Courses-Taken entity will be: CIS 370-Section2-fall2008 and a relationship between the courses-Taken and the students will be drawn.Response: see Appendix 6A Normalizing the data modelDifficulty: hard

How do you validate an ERD?

Ans: Creating and validating ERDs can be tough. It takes experience to draw ERDs well and there are not all that many guidelines and rules. You will want to verify that entities are complete (i.e. have all the needed attributes, have consistent names (not client at some point and customer at another point), that relationships are identified and drawn; that cardinality (1:1; 1:N or M:N) is drawn and if possible M:N cardinalities are avoided by creating entities in between the M:N entities; that modality is identified (null or non-null); and that eventually the ERD is normalized to 3NF. It takes time and patience to learn and do this!!!Response: see Validating an ERD and Appendix 6:A Normalizing the data modelDifficulty: hard

Discuss what should be done to ensure that the entity relationship diagrams balance with the data flow diagrams. What is the consequence of failing to balance these models?

Ans: The key to balancing these diagrams is to remember that both models must refer to exactly the same 'data foundation' of the system. Every entity on the data model should correspond to a data store on a DFD. Also, all the data elements that comprise the data flows in the DFDs should appear as attributes of entities in the data model. Similarly, the attributes of the data model entities should be found in the process models; otherwise, the data is probably not used by the business system and should not be stored. If the analysts do not balance the data and process models, then the system will either omit critical data or will contain unnecessary data.Response: See normalizing / balancing entity-relations diagrams and data flow diagramsDifficulty: hard

Target stores have bridal registries. This registry keeps information about customers (the couple that is to be wed) prior to the wedding and keeps the data for a period of two years after the wedding (for returns or late purchasers), the products that the store carries, and the products that each couple has included in the registry. Couples typically register for a large number of products and many couples register for the same products. Draw an entity relationship diagram for Targets bridal registry:

Ans:Couple (has)Registered Product(includes)Products(one to many)(one to many)(one couple registers many products)(one product is included on many registers)Response: See Creating an Entity-Relationship DiagramDifficulty: hard

What is the relationship between ERDs, DFDs and CASE tools?

Ans: They are inter-related. The Data flows and data stores on DFD process models will be the ERD entities; the CASE tools will hold data dictionaries about the data that is on the data models.Response: see Creating an Entity Relationship Diagram and Balancing Entity relationship diagrams with data flow diagramsDifficulty: hard

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