Essay Questions

Front 1

Define the term “actor”. Give an example.

Back 1

An actor represents anything that needs to interact with the system to exchange information. An actor is a user, a role, which could be an external system as well as a person. E.g. a customer who submits a order.

Front 2

What are the different tools a project manager can use to prioritize and schedule use cases?

Back 2

1/ use-case ranking and priority matrix

2/ use-case dependency diagram

Front 3

List the benefits of constructing a use-case dependencydiagram.

Back 3

1/ graphical depiction of the system's events and their states enhances understanding of system functionality

2/ helps identify missing use cases

3/ helps facilitate project management by depicting which use cases are more critical

Front 4

Differentiate between entities and entity instances. Why don’t we try to model instances?

Back 4

An entity is a class of persons, places, objects, events, or concepts about which we need to capture and store data. An entity instance is a single occurrence of an entity.

In data modeling we do not concern ourselves with individual occurrences or instances of an entity because we recognize that each occurrence of an entity is described by similar pieces of data.

Front 5

Differentiate between candidate keys, primary keys andalternate keys. Can each of these be a concatenated key?

Back 5

A candidate key is a candidate to become the primary identifier of instances of an entity.

A primary key is that candidate key which will most commonly be used to uniquely identify a single entity instance.

An alternate key is any candidate key that is not selected to become the primary key.

All three examples of keys can become concatenated keys.

Front 6

What is an associative entity? What role does it play intenary relationships? What role does it play in resolving nonspecificrelationships?

Back 6

Associate entity is an entity that inherits its primary key from more than one other entity.

The associate entity plays the connecting role in the ternary relationships.

It resolves nonspecific relationships by becoming the connecting factor that resolves many-to-many relationship by using the foreign keys from other entities.

Front 7

What is a “weak” entity?

Back 7

The child entity of any identifying relationship is frequently referred to as a "weak" entity because its identification is dependent on the existence of the parent entity's existence.

Front 8

Differentiate between cardinality and degree?

Back 8

cardinality - shows the complexity of each relationship.

Degree - of a relationship is the number of entities that participate in the relationship.

Front 9

What is subsetting criteria?

Back 9

is an attribute (or concatenated attribute) whose finite values divide all entity instances into useful subsets.

Front 10

Differentiate between data modeling and data analysis.

Back 10

data analysis is a process that prepares a data model for implementation as a simple, non-redundant, flexible, and adaptable database. The specific technique is called normalization.

Normalization is a data analysis technique that organizes data attributes such that they are grouped to form non-redundant, stable, flexible, and adaptive entities.

Front 11

How does a data-to-location-CRUD matrix supplement a datamodel?

Back 11

while a logical data model is effective for describing what data is to be stored for a new system, it does not communicate those requirements on a business operating location basis. The data-to-location-CRUD matrix can supplement the data model by identifying what data can access rights are needed at which locations.

Front 12

Differentiate between a data flow and a control flow.

Back 12

A data flow represents an input of data to a process or the output of data from a process.

A control flow represents a condition or non-data event that triggers a process.

Front 13

What is the difference between data flows and data stores? What is the difference between data flows and data entities? What is the difference between data entities and external entities?

Back 13

A data flow is data in motion, while a data store is data at rest. A data flow represents an input of data to a process or the output of data from a process.

A data stores is an "inventory" of data. A data entity is something about which we want to store data. A data store is all instances of a data entity.

A data entity is something about which we want to store data, while an external entity is a person, organization unit, other system, or other organization that lays outside of the scope of the project, but which interacts with the system being studies.

Front 14

What is a process? Name three types of logical processes.

Back 14

A process is work performed on, or in response to, incoming data flows or conditions. 3 types:

1/ functions

2/ events

3/ elementary (or primitive) processes

Front 15

What is the difference between logical and physical modeling? Why is logical modeling more important in systems analysis?

Back 15

Logical models show what a system is or does. They are implementation-independent. They illustrate the essence of the system.

Physical models show not only what a system is or does, but also how the system is physically and technically implemented.

Logical modeling is important in systems analysis because it removes biases that are the result of the way the current system is implemented or the way that any one person thinks the system might be implemented. It reduces the risk of missing business requirements because we are too preoccupied with technical details. It also allows us to communicate with end-users in non-technical or less technical languages.

Front 16

What purpose does Structured English serve in processmodeling?

Back 16

Structured English is a language and syntax, based upon the relative strengths of structured programming and natural English, for specifying the underlying logic of elementary processes on process models.

Front 17

What is event partitioning?

Back 17

Event partitioning factors a system into subsystems based on business events and responses to those events.

Front 18

What are the basic constructs of Structured English?

Back 18

1/ a sequence of simple, declarative sentences.

2/ a conditional or decision structure.

3/ an iteration or repetition structure.

Front 19

What is the relationship between policy and a decisiontable?

Back 19

A policy is a set of rules that govern some process in the business and a decision table is a tabular form of presentation that specifies a set of conditions and their corresponding actions. The decision tables can be useful for specifying complex policies and decision-making rules.

Front 20

What are the basic constructs of a data structure?

Back 20

1/ a sequence or group of data attributes that occur one after another.

2/ the selection of one or more attributes from a set of attributes.

3/ the repetition of one or more attributes.

Front 21

Define Object Modeling.

Back 21

Object modeling is a technique for identifying objects within the systems environment and the relationships between those objects.

Front 22

What is an attribute? Give several examples of attributesfor an object.

Back 22

Attributes are the data that represent characteristics of interest about an object. E.g. first name, last name, street address, phone number, etc.

Front 23

Explain the concept of message sending for objects /classes.

Back 23

A message is passed when one object invokes another object's method (behavior) to request information or some action.

Front 24

Define the term polymorphism. Give an example.

Back 24

Polymorphism means "many forms". Applied to object-oriented techniques, it means that a behavior may be completed differently for different objects/classes. E.g. A DOOR and a WINDOW may perform the behavior CLOSE differently.

Front 25

Explain the relationship between prototyping, JAD, and RAD.

Back 25

Prototyping, JAD, and RAD are all strategies for systems design that when used in conjunction with each other are successful implementation design tools.

Front 26

Explain the difference between a request for proposal (RFP)and a request for quotation (RFQ).

Back 26

A request for quotation is used when you have already decided on the specific product, but that product can be acquired from several distributors. A request for proposal is used when several different vendors and/or products are candidates and you want to solicit competitive proposals and quotes.

Front 27

Define dependency & navigability.

Back 27

Dependency means that when a change occurs in one class, it may affect another other class. Navigability means that classes with associations between them can send messages. Normally, but not always, the messages can be sent in either direction.

Front 28

Explain the difference between an “initiator” actor and a“receiver” actor. Give an example ofeach actor.

Back 28

An initiator actor initiates the use case and the receiver actor receives the information from the system. E.g. club member and warehouse

Front 29

Define the term object responsibility. Give an example.

Back 29

Object responsibility is the obligation that an object has to provide a service when requested and thus collaborating with other objects to satisfy the request if required.

An ORDER object may have the responsibility to display a customer's order.

Front 30

Identify the three object-oriented design activities.

Back 30

1/ refining the use case model to reflect the implementation environment.

2/ modeling object interactions and behavior that support he use case scenario.

3/ updating the object model to reflect the implementation environment.

Front 31

What is process decomposition and what role does it play inprocess modeling?

Back 31

Process decomposition is when a system is separated into its component subsystems, which in turn are decomposed into smaller subsystems, until such a time as we have identified manageable subsets of the overall system.

In process, modeling decomposition allows you to partition a system into logical subsets of processes for improved communication, analysis and design.