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CSIT114 Lab Exercises

Terms in this set (131)

What is the difference between an information system and a computer application?
Usually a computer application is a single computer program that may or may not be connected to a database.

An information system is normally multiple computer programs that are connected to a database and thus provide as output various types and quantities of information.
What are the five elements in an information system?
Hardware, software, data, processes, and people
What is the difference between systems analysis and systems design?
Systems analysis is to determine the what the new system should do. It is discovery and understanding.

Systems design is to determine how the new system should be built. It is structure and architecture.
What is an Enterprise resource planning (ERP) system?
An ERP system is the integrated management of main business processes, often in real time and mediated by software and technology.

ERP is usually referred to as a category of business management software—typically a suite of integrated applications—that an organization can use to collect, store, manage, and interpret data from many business activities.
What is the purpose of the system development life cycle (SDLC)?
It provides a framework, including methodologies, models, tools and techniques, to build and deploy an information system.

Its purpose is to provide structure and organization to the development process.
What are the six core processes for software systems development?
1) Identify the problem.
2) Plan and monitor the project.
3) Discover and understand the requirements.
4) Design the system components.
5) Build, test, and integrate the system components.
6) Finalize testing and deploy the solution.
What are the relationship between systems analysis and design and other activities in SDLC?
Systems analysis and design provides the tools and techniques which are needed by an information system developer in order to complete the development process.

Those tools and techniques are used throughout the whole SDLC, not just the analysis and design processes.
What is meant by Agile Development and iterative development?
Agile development is a philosophy of systems development that emphasizes flexibility to handle changing requirements during the development project.

Iterative development is a broader term that defines several iterations of defining and building the new system. It is an approach to incrementally build a new system.

Agile development is one methodology that supports iterative development.
Define project management
Project management is the organizing and directing of other people to achieve a planned result within a predetermined schedule and budget
How is scope management accomplished with Agile project management?
Since Agile projects are more flexible, frequently there are more requests for additional functionality to be added. To control these requests a prioritised list of functions is maintained. In order for new functions or requirements to be added, they must go through a review process and be added to the prioritised list.
List some internal responsibilities of a project manager?
- Developing the project schedule
- Recruiting and training team members
- Assigning work to teams and team members
- Assessing project risks
- Monitoring and controlling project deliverables and milestones
List some external responsibilities of a project manager?
- Reporting the project's status and progress
- Working directly with the client (the project's sponsor) and other stakeholders
- Identifying resource needs and obtaining resources
What are the four activities of Core Process 1?
- Identify the problem
- Quantify the project approval factors
- Perform risk and feasibility analysis
- Review the approval factors with the client to obtain approval
What are three reasons that projects are initiated?
- To respond to an opportunity
- To resolve a business problem or need
- To respond to an external (such as legal) mandate
What is the difference between system capabilities and business benefits?
The business benefits are usually measured in the dollars that are brought to the organization, either as increased revenue or reduced costs. Intangible benefits are those where a dollar amount cannot be easily assigned, but still will add value to the organization.

The system capabilities are the functions that support the business procedures. The system capabilities are those things that enable or lead to the business benefits.
What factors are usually considered when approving a project?
- How long will the project take?
- How much will it cost?
- What are the anticipated benefits to the organization?
What is Cost/Benefit Analysis? Using the following example, also explain Net Present Value (NPV), Break-Even Point and Payback Period
- Cost/benefit analysis: comparing costs and benefits to see if the net result is plus or minus

- Net Present Value (NPV): the present value of dollar benefits and dollar costs of a particular investment

- Break-even Point: point in time at which benefits and costs are equal

- Payback Period: the time period after which the dollar benefits have offset the dollar costs
List four different types of major risks that may cause problems for a project.
Organizational risks - whether the organization and employees are ready for a new system.

Technological risks - new systems frequently require new technology with accompanying risks.

Resource risks - does the organization have sufficient resources and people with required skills?

Schedule risks - is the schedule realistic and can the milestones be completed on time?
What are the five activities of Core Process 2?
- Establish the project environment.
- Schedule the work.
- Staff and allocate resources.
- Evaluate work processes.
- Monitor progress and make corrections.
What is the difference between the project iteration schedule and the detailed work schedule?
The project iteration schedule is a broad, overview schedule that identifies all iterations and the use cases or functions assigned to each iteration. Generally this schedule is not detailed enough to assign work.

The detailed work schedule is a shorter view and more detailed schedule, such as for each iteration, from which work assignments can be made and progress can be measured.
What is a work breakdown structure used for?
The work breakdown structure is the first step in building a detailed work schedule. It identifies all of the pieces of work that must be done to complete a certain milestone or that covers a period of the project.

It also describes how much effort is estimated for each task.

But it needs not to contain dependence information about tasks.
List three guidelines for identifying tasks on the WBS.
Three guidelines to help determine the size and scope of tasks are:
- There should be a way to recognize when the task is complete.
- The definition of the task should be clear enough so you can estimate the amount of effort required.
- As a general rule for software projects, the effort should take one to five working days.
What is a Gantt chart? What is it used for?
A Gantt chart is a bar chart with horizontal bars that depict the dependence between tasks and the amount of time required for each task. The horizontal scale is a calendar, either days or dates.
What is a critical path? Why is it important for the project manager to watch the tasks on the critical path?
The critical path is the sequence of tasks that must occur in order (one after the other) that must be completed on time or the project is delayed. It represents the longest path (i.e. sequence of tasks) through the project and it determines the shortest amount of time required to complete the project.
List and briefly describe the five activities of systems analysis.
Gather detailed information - meet with users to understand the business processes and needs

Define requirements - document findings by building models such as use case diagram and class diagram

Prioritize requirements - Decide which requirements (such as use cases) should be done first

Develop user-interface dialogs - work with the users to define exactly how they will use the system and what interactions with the system are required

Evaluate requirements with users - ensure that the requirements are complete, accurate, and prioritized correctly
What are three types of models?
Textual models, graphical models, and mathematical models
What is the difference between functional requirements and nonfunctional requirements?
Functional requirements describe the business rules that must be supported by the new system, while non-functional requirements are the system characteristics such as speed, throughput, response time, and security. Both are important!
List and briefly describe the six information gathering techniques.
Information gathering techniques include
- Interview users and stakeholders - the most effective for information gathering, but the most expensive
- Distribute questionnaires - good for finding overview or summary information from many people
- Review current system documentation - good for understanding current processes
- Observe current business processes - also good for understanding the user's processes and requirements
- Research vendor solutions - good for generating new ideas and learning what already has been done Collect user comments - good for finding out about problems with current processes
What is the difference between system capabilities and business benefits?
The business benefits are usually measured in the dollars that are brought to the organization, either as increased revenue or reduced costs. Intangible benefits are those where a dollar amount cannot be easily assigned, but still will add value to the organization.

The system capabilities are the functions that support the business procedures. The system capabilities are those things that enable or lead to the business benefits.
What is the purpose of an activity diagram?
One purpose of an activity diagram is to document current user workflows. Activity diagrams are often called workflow diagrams. They can be used to document a user procedure as he/she interacts with the computer system.
Explain why the Unified Modelling Language (UML) is important to use as a standard for creating information systems models.
Prior to UML there was no standard so diagrams would vary between companies and even within a company. This caused confusion and also discrepancies or gaps in the requirements definition. There also was no standard that was taught in university level courses and textbooks. This caused problems in both student preparation and in the ability of students to adapt to different company methods and models.
What is a user story?
A user story is a short one sentence description from the user about what he/she does as part of his/her work.
What is a use case?
A use case is an activity that the system performs as a result of some event or action by a user.
What are the two techniques used to identify use cases?
User goal technique and the event decomposition technique
Describe the user goal technique for identifying use cases.
The user goal technique is done by interviewing a user (or user role) to see what their work "goals" or objectives are. These are low level objectives to accomplish a piece of work or to complete a work procedure. The system then must have use cases to support each user goal.
Can you provide some examples of use case names that correspond to your goals as a student going through the subject enrolment process? Be sure to use the verb-noun naming convention.
For example, "View all subjects", "Enroll into a subject", "Withdraw from a subject"
What is the overarching objective of asking users about their specific goals?
To discover and document every use case that the system must support.
The first step of the user goal technique is identify the different types of users. How to would you identify user types?
Consider users with different functional roles, e.g., shipping, or sales, or accounting.

Also consider users at different organisational levels, e.g., clerks, or middle management like supervisors, and then executives
Can different types of users have the same user goals for using the system?
Yes. For example, users from different departments can access the same use cases, e.g. can have the same user goal for using the system
Describe the event decomposition technique for identifying use cases?
Look at all of the business processes that result in some type of business event. The business events are triggers that require system processing, e.g. that require use cases.
Why is the event decomposition technique considered more comprehensive than the user goal technique?
Event decomposition not only looks at user initiated events (the same as the user goal technique), but it also considers temporal events and state events. Hence it is more comprehensive.
What is an elementary business process (EBP)?
An EBP is a fundamental business process that may input data and receive information, but upon completion of the EBP the system has finished processing and can enter a quiescent state ready for a new event
Explain how the event decomposition technique helps identify use cases at the right level of analysis.
Since event decomposition depends on EBP, then it automatically arrives at the right level of analysis. EBP, where the system has finished a complete transaction, is the same level that is required for a use case definition.
What is an event? What are the three types of events?
Something that occurs at a specific time and place. It can be identified, and for purposes of systems analysis, the system must recognize it and capture some information from it or about it.
- External event - usually from a user
- Temporal event - occurs at a point in time, or due to a time interval
- State event - a change of state or condition of some data within the system
Give an example of external events that applies to a checking account system.
An example might be that a user makes a direct deposit to his/her account.
Give an example of temporal events that applies to a checking account system.
An example might be that at the end of the month interest (or monthly checking account fee) is calculated and credited to the account.
What are system controls, and why are they not considered part of the users' functional requirements?
System controls are safety procedures or mechanisms that protect the system and the data. They are not part of the users' functional requirements because the users normally do not initiate nor activate these controls. They must exist above and overriding the external events. These controls are not normally part of the users' work processes.
Provide some examples of events that are system controls in a typical information system but not be included as a use case because of the perfect technology assumption?
For example, "Backing up a database", "User logging onto the system", and "Restoring the database"
What is the purpose of UML Use Case Diagrams?
Use Case Diagrams provide a graphical view of use cases and the actors that invoke those use cases. They provide a nice overview of use cases. They can organise use cases together in meaningful ways.
What is another name for "actor" in UML? How many actors can be related to a use case on a use case diagram?
An actor is also an external agent. In a use case diagram it is represented as a stick figure.

As many as necessary. All those that use that particular use case
Why might a systems analyst draw many different use case diagrams when reviewing use cases with end users?
An analyst will draw different use case diagrams to organise the use cases in different ways to illustrate different subsystems, or departments, or work associations.

The purpose of doing so is documentation and communication (e.g., with stakeholders and development team members).
What is the problem domain?
The area of the user's business need. It is called "problem" because there is a need or something to be fixed. It is the domain, or the area of the business.
What is a "thing" called in models used by traditional analysts and database analysts?
Data entity
What is a "thing" called in newer approaches that use UML?
Object or object class
What are two techniques for identifying things in the problem domain?
The Brainstorming technique and the Noun technique
What are the main steps of the brainstorming technique?
1. Identify a group of users and their related use cases.
2. Brainstorm with this group about all the things they need to keep track of with these use cases.
3. Expand the list of things by asking related questions about locations, roles, etc.
4. Return to step 1 with different groups of users.
5. Combine and merge, eliminating duplicates
Explain why identifying nouns helps identify things in the problem domain?
Nouns are always "things." So finding all the nouns will find all the things (and more, so it needs to be refined).
What are the main steps of the noun technique?
1. Using use cases, dialogs, conversations, etc. list all the nouns.
2. Using information from existing systems, etc. list all the nouns.
3. Refine the list by asking three questions for each noun - Include it? Exclude it? Research it?
4. Create a master list out of step 3.
5. Review the list with users, stakeholders, and other team members.
What is an attribute, an identifier or key, and a compound attribute?
An attribute is a descriptor of a data entity (Object). For example a Customer (object) has a name (attribute). So although attributes are also nouns, they are descriptor or qualifier nouns.

An identifier or key is an attribute that can uniquely identify a particular object.

A compound attribute is an attribute consists of "sub-attributes" or components, like address consists of street, city, state, postal code.
What is an association, and what system development standard defines it?
An association is a relationship between things in the problem domain. It is the term used by UML.
What is a class, a domain class, and the key parts of a class diagram?
A class is a set of objects that are similar in nature had have the same "classification."

A domain class is a class in the problem domain.

A class diagram has classes with attributes, associations/other relationships, and multiplicity constraints.
What does a Domain Model Class Diagram show about system requirements?
A domain model shows the classes, i.e. the things, and their relationships and constraints. These are the specific system requirements that must be built into the database.

The problem domain classes are the classes from the domain and are "persistent", e.g. they must be stored in a database.
What is an association class?
An association class is where an association must also be treated as a class. In other words, the instances of the association relationship are also instances in a class.

It is normally used when there is many-to-many association that also must have attributes associated only with the association and not either of the endpoint classes
In UML, what are three types of relationships found on a class diagram?
Regular association, Generalization/Specialization, Whole-part
What is a generalization/specialization relationship, and what object-oriented terms does it illustrate?
A generalization/specialization is a hierarchical relationship between classes, where some classes are subsets (e.g. subclasses) of other classes
Compare/contrast superclass and subclass. Also compare/contrasts abstract class and concrete class.
A superclass is higher in the relationship hierarchy and is a superset. A subclass is lower and is a subset of the superset.

An abstract class is a class with no objects allowed. It serves only as a template for attributes so that subclasses, which are concrete classes, will have objects with inherited attributes.
What is a whole-part relationship, and why does it show multiplicity?
A whole-part relationship in which a class is part of another class. It can have multiplicity constraints that allow multiple part-classes to belong to a single whole class.
What is an object state?
An object state is a condition during an objects life. When an object is in a state it satisfies some criterion, or is performing an action, or is waiting for an event.
What is a state transition?
A transition is the movement of an object from one state to another state.
What is the purpose of a UML State-Machine Diagram?
To show the states and transitions for an object.
What is meant by the term path?
A path is a sequential set of states that are connected together with transitions.
Explain the difference between a use case and a scenario. Give a specific example of a use case with a few possible scenarios.
A use case is the entire function or user goal or event. A scenario is one specific version or instance of that use case.

From RMO we have Create customer account as a use case. But we might have Create online Customer account and Create instore customer account and even Create phone customer account as different scenarios.
Compare/contrast precondition and postcondition
A precondition describes the "states" of data and the system that must exist before the use case can begin. For example to add an item to a shopping cart, the item must exist in the database.

A postcondition describes the states of data and the system that must exist after the use case completes. For example after Create a customer account use case, a customer account object (record) must exist
Compare/contrast postcondition and exception condition
A post condition, as explained about describes states of the data and the system. An exception condition describes some non-normal situation in the processing, i.e. in the flow of activities, that must be handled in some way.
Compare/contrast business process and flow of activities for a use case. Explain how an activity diagram can be used to model both.
A business process is larger than a use case.

A business process might include various manual business procedures both before and after the "business event" that causes the use case to occur.

However, an activity diagram is a powerful model to describe all types of sequences of tasks and activities. The various swimlanes can represent various users or user groups as well as system activities.
What are the words included in the CRUD acronym?
Create, Read/Report, Update, Delete
What is the purpose of using the CRUD technique?
To ensure that every class has sufficient use cases to "cover" all the required actions. Every object in a class in the new system must be instantiated, must be able to be edited or updated, must be able to be access for reporting and processing, and in most cases should be deleted or archived.
Summarise the Activity Diagrams, SSD and Fully Developed Use Case Description, and their relationship to one another
An Activity Diagram is used to document the sequence of steps or the work flow of a use case.

A System Sequence Diagram is used to document the interactions between the external actor and the system.

A Fully Developed Use Case Description is used to document the details of a use case, including such things as pre- and postconditions as well as the sequence of steps
How does the objective of systems analysis differ from the objective of systems design?
The objective of systems analysis is to understand the needs and requirements, while the objective of design is to figure out the solution to those needs and requirements. Analysis is to understand the problem, design is to solve the problem. (And Implementation is to build the solution.)
What are the inputs to systems design? What are the outputs?
Inputs primarily are the requirements models. This includes domain model class diagram, use case diagrams, use case descriptions, activity diagrams, system sequence diagrams, and state-machine diagrams.

Outputs are the design models. This includes the design class diagram. Interaction diagrams, design state-machine diagrams, package diagrams, deployment diagrams, and component diagrams.
List and briefly describe each design activity.
- Describe the environment - to research and describe the configuration and existing hardware and software of the current computing environment and of external systems requiring interfaces.
- Design the application components - this is structural or architectural design to configure the components, such as subsystems, that will be included in the final system.
- Design the user interface - this consists of designing the user screens and reports for the new system.
- Design the database - this involves using the class diagram to design the database schema.
- Design the software classes - this involves determining the classes and the methods within each class to carry out each use case.
Why is the environment described while other key design elements such as the user interface and database are designed?
Most new systems are developed to be integrated into an already existing computing environment. Hence the task is to understand the existing environment that the new system must fit into. This normally includes such things as DBMS, Operating Systems, Network, programming standard languages, and existing hardware.
Compare and contrast integrity controls and security controls. Why isn't there a separate activity to design them?
Integrity controls have to do with the maintaining the integrity of the data as it is entered into the system, processed and stored within the system and output from the system. Security controls are more associated with the entire environment from primarily external threats that are malicious. Designing integrity and security controls must be part of every other design activity and hence is not considered a stand-alone design activity.
Is the Internet the same thing as the World Wide Web? Why or why not?
The Internet is comprised of the computers and network transmission components (fiber, cables, areal transmission) and the system software that handle and distribute the messages and the signals.

The WWW consists of all the resources that are available over the Internet. So all the servers that manage and distribute resources, such as Web pages, are part of the WWW but not necessarily the Internet.

So the WWW resides on top of and provides resources via the Internet.
What is the role of protocols in modern software and systems?
Protocols are kind of like the glue that holds the software and hardware together. It is a set of languages, rules and procedures that set the standards so the different hardware and system software know how to communicate and interface together.
Briefly define the terms technology architecture and application architecture. How are they different? How are they interdependent?
The technology and technology architecture is the underlying computer hardware, network hardware and system software configuration that is used by an organization. It is the "platform."

Application architecture is all the software that resides on top of the technology architecture, and which is used by the business to carry out its daily operations. It is called an architecture because it has to work together in an integrated fashion as a complete working environment.
Describe the parts of a URL: http://www.amazon.com/gp/cart/view.html/ref=nav_cart
- http: is the protocol header, which indicates what is the format of the message
- "www.amazon.com" is the server name or address. This will translate to an IP address
- "/gp/cart/cart/view.html" is the resource location and name.
- "ref=nav_cart" is an argument that specifies in more detail the resource name.
List and briefly describe the function of each layer of threelayer architecture. On what type of computing device is each layer typically deployed?
The view layer is usually deployed on the client computer. However this is not exclusive. Portions of the view layer also reside on the server. For example for a Web based system, the HTML can be considered the View Layer. The HTML is generated on the server and displayed on the client. Both activities can be considered view layer functions.

The business logic layer, or domain layer, is where the business functions reside. Usually the domain layer will reside on the server since it is the logic of carrying out the business functions. However, there are also exceptions to this in that the browser may contain code (such as javascript) that may perform calculations or perform some, usually limited, business functions.

The Data layer is where the data is stored and the logic required to access it and maintain it in a consistent state. Almost always this will deployed on the server.
In what way(s) is three-layer architecture different from client/server architecture? In what way(s) is it similar?
Client/Server architecture is a conceptual approach where functions are provided by a server and consumed or used by a client. It does not specify the form of either the client or the server other than that they are separate components.

Three-layer architecture is a more specific configuration for a client/server architecture where the software is divided into view layer (usually the client), business logic layer (usually part of the server), and data layer (also part of the server).
Compare and contrast application and system software. List a few specific examples of each type.
Application software performs user and business tasks, such as an accounting or point-of-sale system.

System software performs the underlying tasks of providing a platform for the application software. Examples of system software is operating systems (Windows) and server software (Microsoft IIS). Oftentimes system software is lower-level software, in that it interacts more closely with the computer and network hardware.
Describe how an object-oriented program works?
View objects (windows) receive inputs, and send and receive data via messages to business layer objects. As required, business objects send and receive data to database access objects, which retrieve and update the database. The basic approach is that an object-oriented program is a set of interacting objects that get work done sending messages and requesting services from each other.
What is instantiation?
It is the process of creating a new "instance" of an object using the template provided by the class definition
List the models that are used for object-oriented systems design
The primary UML models are design class diagrams, Interaction diagrams (sequence diagrams and communication diagrams), and package diagrams. Although not a UML model, CRC cards can also be considered a model. Not discussed in the lecture, but state-machine diagrams area also used during design.
Explain how design classes are different from domain classes.
Domain classes usually contain the class name and a list of attributes. Design classes extend domain classes by type casting the attributes, identifying keys, identifying initial values. Design classes also include method signatures with return type and passed parameters.
What is the difference between a system sequence diagram and a sequence diagram?
A system sequence diagram only has two objects, the external actor and the system. It is used to document the messages that flow into and out of the system - in other words the input and the output messages. A sequence diagram explodes the system object to show all the internal objects that interact to process each input message.
List the steps for doing object-oriented detailed design.
- Since design is done use case by use case, the first step is to choose a use case.
- Develop a first-cut design class diagram.
- Depending on the complexity of the use case, the developer does detail design using CRC cards, or Communication diagrams or Sequence diagrams.
- Take information from the detailed design model and create a final design class diagram
- Combine classes, as appropriate, into packages with a package diagram
What do we mean by use-case driven design?
Use-case driven design means that detailed design is performed on a use-case by use-case basis. Use case realization, as explained in the next chapter, is the process of identifying and defining all of the internal messages (methods) between the view layer, business logic layer, and data access layer objects for the specified use case
What does coupling mean and why is it important?
The coupling is the amount of connectedness between classes. Strong coupling, or high coupling, means that two or more classes are very closely associated with each other. Ideally classes are loosely coupled so that programming changes to one do not also require changes to the other class. So coupling is a concept describing the relationship between classes.
What does cohesion mean and why is it important?
Cohesion is an internal concept to describe the "focus" or "unity" within a class. A class with high cohesion is easier to maintain because it does not have a lot of extraneous methods of functions that may be negatively impacted to programming changes.
Compare and contrast the ideas of coupling and cohesion.
Coupling is a measure about relationships between classes, while cohesion is a measure within a class. Coupling relates to the entire system, or all the classes in a system. Cohesion relates to a single class. In system design we try to achieve low coupling and high cohesion.
What is protection from variations, and why is it important in detailed design?
Protection from variations is a technique to isolate or segregate those portions of the system that change frequently from those portions that are more stable. By isolating the less stable portions, changes can be made without having to investigate large portions of the system. It isolates the changes to a few classes.
What is object responsibility, and why is it important in detailed design?
Object responsibility is a principle to help decide which classes should have which methods. By considering object responsibility during design, the result is a set of classes with high cohesion. Classes are given responsibility for their own data and for their own functions.
What is meant by separation of responsibilities?
Separation of responsibilities is a design concept where groups of classes have a primary focus and can be grouped together. It is the basis for three-layer design.

For example, view layer classes have responsibilities only to display data and accept inputs. The do not have responsibility to do business logic.

Another example is dividing a system into subsystems to only carry out certain functions. For example a class or a set of classes may have responsibility to calculate taxes within a point of sale system.
What are:
a) persistent classes,
b) entity classes,
c) boundary classes,
d) controller classes, and
e) data access classes?
- Persistent classes are those where the data must be stored between program executions, usually in a database. The genesis of persistent classes are usually the problem domain classes.
- Entity classes are the business classes, which also come from the problem domain classes.
- Boundary classes are the view layer classes
- Controller classes are those classes that act as the interface between the view layer and the business layer. These classes are like switchboard classes.
- Data access classes are those in the data layer and contain the logic necessary to read and write to the database.
What is a method signature?
A method signature is a unique identifier of a method. Depending on the programming language, it usually consists of the method name, the return type, and the list of all the parameters with the type of each.
Compare and contrast abstract and concrete classes. Give an example of each.
An abstract class is one which cannot have any objects instantiated. A concrete class does allow for objects to be instantiated.

For example, an abstract class might be a "vehicle", with concrete subclasses of "car" and "truck." There are no vehicles that are not also a car or truck.
Describe navigation visibility. Why is it important in detailed design?
Navigation visibility is the ability of the objects in one class to have a reference to, and thus access the API, of the objects in another class. Obviously, if a class does not have a reference to another class, it cannot access its methods. It is a critical design concept.
List some typical conditions that dictate in which direction navigation visibility occurs.
A superior/subordinate relationship with the superior being able to view the subordinate

Mandatory relationship such as a client and order. A client object should know about its orders.

Informational requirements will need visibility to access the class with the information
What information is maintained on CRC cards?
CRC cards have one card for each class. On the card are listed the class name, the responsibilities (which are like the methods), other classes that are required to collaborate, and on the back a list of the attributes for that class.
What is the objective of a CRC card design session?
A CRC design session is to define a set of collaborating classes (i.e. a set of CRC cards) that work together to carry out a use case. It is a simple way to do use case realization.
How are CRC cards used to update the DCD (Design class Diagram)?
CRC cards identify responsibility of the classes. These responsibilities refer to the methods that a class may require.
What is the system development life cycle (SDLC)?
SDLC is the term used to describe the process and methodology for developing, deploying, and maintaining a software system. A particular SDLC will include a description of the methods, the tools, techniques, models, and project management processes that are used in the development of a new system.

It is called a life cycle because it can cover the entire life of a system from initial idea to deployment to ongoing maintenance.

The six phases of the traditional predictive SDLC are: Project initiation, Project planning, Analysis, Design, Implementation (programming) and Deployment

The SDLC used in this text is a simplification of and variation on the Unified Process (UP), which is a well-known and well-accepted formal iterative approach.
What characteristics of a project call for a predictive approach to the SDLC?
Predictive: Projects are well understood—technology is well known; user requirements are well known; development methodology is well known; project team is experienced and familiar with the system; and there are few known risks.
What characteristics of a project call for an adaptive approach to the SDLC?
Adaptive: Projects are not well understood—technology is new or unfamiliar; requirements are not very clear; team is not experienced with the type of system or methodology.
Explain how the waterfall model of the SDLC controls the changes that occur during a project.
The pure waterfall attempts to specify completely the requirements during the analysis phase, and then tries to "freeze" those requirements so that things do not change. Another solution is to have a modified waterfall so that additional analysis (i.e. specifying new requirements) can be done as the project progresses. However, neither situation is well suited to handle big changes during the life of a project.
Explain the advantages of having the phases of a predictive SDLC overlap.
Having overlap allows the project to handle ongoing analysis and requirements definition even after design and programming have begun. Another advantage is that the development team can work more efficiently by doing design and even programming on those requirements and specifications that are being worked on (i.e. in analysis).
What is the iterative approach that involves completing and deploying part of an application over a few iterations and then completing and deploying another part of that application after a few more iterations?
This is usually referred to as incremental development. A variation of incremental development that builds the entire structure at first is called a walking skeleton.
Why do adaptive SDLCs not explicitly include the support phase?
Support does not fit into an "iteration" project model. Hence, the Support Phase is either treated as separate follow-on projects, or it reverts back to the predictive model and becomes a Support Phase.
What is a system development methodology?
A methodology is more than just a method. It is an entire set of guidelines and procedures to develop a new system. Included in the components of a methodology would be what modelling approach to use, what tools, what techniques to do analysis and design and programming. A methodology provides the guidelines for the entire development process.
What is Agile development?
Agile development is a philosophy and set of guidelines for developing information systems in an unknown, rapidly changing environment, and consists of a statement of core philosophy and a set of values or guidelines for how to build models.

The four basic values of the core philosophy are:
- Value responding to change over following a plan
- Value individuals and interactions over processes and tools
- Value working software over comprehensive documentation
- Value customer collaboration over contract negotiation
What is Agile modelling (AM)?
Agile modelling is a guiding philosophy about modelling. Only models that are necessary to move the project forward and that are really needed for the development of the software
As a system development methodology, how is UP aligned with the SDCL?
There are 9 UP principles (6 for development and 3 for management) and 4 UP Phases. Their alignment with the SDLC are shown by the following two figures: (Lab 10 Slide 4/4)
List and briefly describe each activity of the SDLC core processes "Build, test, and integrate system components"?
Program the software - the programmers write the code

Unit test the software - the programmers test the code they have programmed

Identify and build test cases - this requires both project staff and end users. There are often test cases to be used for integration and system test. Additional end user test cases, which uses or simulates live data, are usually more complex.

Integrate and test components - as components successfully pass unit test, they are integrated into a growing overall system and tested as part of the integrated system.
List and briefly describe each activity of the SDLC core processes "Complete system tests and deploy solution"?
Perform system and stress tests - after the components are integrated successfully, then the entire system is tested to test cross functions, cross time periods, and high volumes.

Perform user acceptance tests - user tests must be done with many kinds of test data, testing both good and bad situations, and verifying all use cases.

Convert existing data - if the new system replaces an existing system valid data, such as customer accounts, must be converted to the new database format.
What is the purpose of unit testing? Who performs it? How is the test data prepared?
Unit testing tests a small component, such as a module, a method, or a class in isolation to make sure that it works correctly before it is integrated into the larger system.

Unit testing is usually done by the programmer who programmed the component using his own test data.
What is the difference between unit testing and integration testing?
While unit testing is small and done by the programmer, integration testing is a more complex endeavour and often requires the work of several people to be tested together. It requires more coordination for the testing.

For unit testing when errors are found, the programmer just corrects them. For integration testing, errors are usually logged and assigned to the appropriate developer, fixed, and retested. This requires some type of error tracking system.
What are the objectives of integration testing?
Integration testing tests to things. It tests both the correct performance of the integrated components as a unit. It tests the functional behaviour of a group of classes as they work together.

Integration testing also tests the interfaces between the smaller units as they are integrated together.
What distinguishes integration testing from system testing? What kinds of tests can be included in system testing?
System testing is the next step up from integration testing.

The scope of the testing is broadened, first to include the entire system, or major components of the system.

And second the types of tests done with the system are also expanded. System testing includes various types of performance testing, and response times. It also includes testing the system under adverse conditions to test stability.

Finally, it also tests the basic functionality of the specified functions.
Who is responsible for user acceptance testing (UAT)? What are the primary objectives of UAT?
UAT, as the name implies, is the responsibility of the client and its representatives, which in most cases is the user. Of course, the user does not usually have all the skills and resources to prepare and conduct the UAT, so the development team is also involved.

The primary objective of the UAT is to ensure that the specified functionality and identified business requirements are supported and processed correctly and adequately by the new system. In other words, does the system do what it is supposed to do - as determined by the user
What is a test case? What are the characteristics of a good test case?
A test case is a predefined set of data to test a particular function or set of functions. Both the input data and the expected results are normally defined beforehand.

Test cases must ensure that all instructions in a program are executed, preferably many times, with a variety of data inputs.
What is a driver? What is a stub? With what type of test is each most closely associated?
A driver is a module that simulates the calling behaviour of a module that hasn't yet been developed. Drivers are most closely associated with unit testing.

A stub is a module that simulates the execution or behaviour of a module that hasn't yet been developed. Stubs are most closely associated with unit testing.
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