OMIS 462 Quiz 3

Data dictionaries:

are created in a top-down matter

Packages:

are groups of things and show partitioning.

Data flow diagrams (DFDs)

are one of the main methods available for analyzing data-oriented systems.

A data dictionary:

is a main method for analyzing the data flows and data stores of data-oriented systems.

The Unified Modeling Language (U M L):

is a notation for modeling object oriented systems.

The rules for creating sequence diagrams are:

that all interface classes must be connected to a control class, and all entity classes must be connected to a control class as well.

Inheritance is when:

a specialized class inherits attributes and methods from the general class.

An attribute describes some property this is possessed by:

all objects of a class.

Data stores may be determined by:

analyzing data flows. Each data store should consist of elements on the data flows that are logically related, meaning they describe the same entity.

An input flow from an external entity is sometimes called a ________, because it starts activities

trigger

Decision tables provide a way to examine, describe, and document decisions using a table consisting of four quadrants. They are used to:

(1) describe the conditions, (2) identify possible decision alternatives, (3) indicate which actions should be performed, and (4) describe actions.

The decision tree has three main advantages over a decision table.

+First, the order of checking conditions and executing actions is immediately noticeable. +Second, conditions and actions of decision trees are found on some branches but not on others, unlike decision tables where they are all part of the same table. +Third, compared to decision tables, decision trees are more readily understood by others in the organization.

Four basic symbols are used to chart data movement on data flow diagrams. They are:

A. A double square for an external entity—a source or destination of data B. An arrow for movement of data from one point to another C. A rectangle with rounded corners for the occurrence of transforming process D. An open-ended rectangle for a data store

The following conditions are errors that occur when drawing a data flow diagram:

A. A process that has only input data flow to it or only output data flow from it. B. When data stores or external entities are connected directly to each other, in any combination. C. Incorrectly labeling data flow or objects. Examples are: i. Labels omitted from data flow or objects ii. Data flow labeled with a verb iii. Processes labeled with a noun D. Too many processes on a data flow diagram. Nine is the suggested maximum. E. Omitting data flow from the diagram. F. Unbalanced decomposition between a parent process and a child diagram. The data flow in and out of a parent process must be present on the child diagram.

Class diagrams include:

A. A rectangle, representing a class B. Attributes, along with notation to indicate whether attributes are private, public, or protected C. Methods used by the class

The most commonly used U M L diagrams and documentation are:

A. A use case diagram B. A use case scenario (not a diagram) C. An activity diagram D. A sequence diagram E. A class diagram F. A statechart diagram

A use case describes three things:

A. An actor (user) that initiates an event B. An event that triggers a use case C. The use case that performs the actions triggered by the event

There are several types of classes:

A. An entity class, storing information about real-world objects B. A boundary or interface class, showing user or other interfaces C. Abstract classes used in generalization/specialization relationships D. Control classes that coordinate the activities of other classes

Detailed data flow diagrams may be developed by:

A. Analyzing what happens to an input data flow from an external entity. B. Analyzing what is necessary to create an output data flow to an external entity. C. Examining the data flow to or from a data store. D. Analyzing a well-defined process for data requirements and the nature of the information produced.

Relationships are associations between classes. There are several types of relationships:

A. Associations, showing the connection between classes. Multiplicity refers to the type of association, such as one to many or many to many. B. Whole/part relationships, where one class represents the whole and other classes represent parts contained in the whole. C. Aggregation, which is a weaker form of a whole/part relationship. The whole may be removed but the parts still exist. D. Collection is a weak whole/part relationship, where the whole retains its identity if the parts change. E. Composition, a strong whole/part relationship where the parts are removed if the whole is removed.

Elements (or fields) are categorized as either:

A. Base elements that are keyed into the system B. Derived elements, which are the result of some operation, such as arithmetic or logic

Advantages of logical data flow diagrams are:

A. Better communication with users. They are familiar with how the business operates. B. More stable systems, because the design is based on a business framework. C. Increased understanding of the business by analysts. D. The system will have increased flexibility and be easier to maintain. E. Elimination of redundancy.

Physical data flow diagrams show how the system operates or how the new system will be implemented. Physical data flow diagrams include:

A. Clarifying which processes are performed by humans (manual) and which are automated B. Describing processes in greater detail C. Sequencing processes in the order they must be executed D. Temporary data stores and transaction files E. Specifying actual document and file names F. Controls to ensure accuracy and completeness

There are four active behavioral relationships:

A. Communicates, is used to connect an actor to a use case B. Includes, describes the situation where a use case contains a behavior that is common to more than one use case C. Extends, describes the situation where one use case possesses the behavior that allows the new use case to handle a variation or exception D. Generalizes, implies that one thing is more typical than the other thing

Other U M L diagrams include:

A. Component diagrams, showing an overview of the system architecture. B. Deployment diagrams, illustrating the physical implementation of the system, including the hardware and relationships between hardware and the system on which it is deployed. C. Annotational things, which are notes that can be attached to anything.

The progression of creating data flow diagrams is:

A. Create a logical data flow diagram of the current system. B. Next, add all the data and processes not currently in the system which must be present in the new system, giving a logical data flow diagram for the new system. C. Finally, derive the physical data flow diagram for the new system.

Data dictionaries may be used to:

A. Create reports, screens, and forms B. Generate computer program source code C. Analyze the system design for completion and to detect design flaws D. Create XML document structures

An activity diagram is created for one use case and shows the different possible scenarios. Activity diagrams include:

A. Decisions, shown by a diamond B. Parallel activities C. Sequential activities D. Partitioning, using swimlanes

The steps used in U M L are:

A. Define the use case model B. Derive the activity diagrams C. Create sequence and collaboration diagrams D. Develop class diagrams E. Draw statechart diagrams F. Refine the U M L diagrams and use them to derive classes, attributes, and methods

An algebraic notation is used to represent the data structure. The symbols used are:

A. Equal sign = meaning "consists of" B. Plus sign + meaning "and" C. Braces {} meaning repetitive elements, a repeating element or group of elements D. Brackets [] for an either/or situation E. Parentheses () for an optional element

To use structured English, the following steps are needed:

A. Express all logic in terms of sequential structures, decision structures, case structures, or iterations. B. Use and capitalize accepted keywords such as IF, THEN, ELSE, DO, and PERFORM. C. Indent blocks of statements to show their hierarchy (nesting) clearly. D. When words or phrases used have been defined in a data dictionary, underline those words or phrases to signify that they have a specialized, reserved meaning. E. Be careful when using "and" and "or" operations, and avoid confusion when using logical comparisons such as "greater than" and "greater than or equal to."

Correct naming of data flow objects is necessary for good communication. Guidelines are:

A. External entities should be named with a noun. B. Processes should be named: i. A system name ii. A subsystem name iii. With a verb-adjective-noun format C. Processes should have a unique reference number. D. Data stores should be named with a noun.

Class, responsibilities, and collaborators (C R C) cards are used to represent the responsibilities of classes and the interaction between the classes. Analysts create C R C cards:

A. Find all the nouns and verbs in a problem statement. B. Create scenarios that are actually walkthroughs of system functions. C. Identify and refine responsibilities into smaller and smaller tasks, if possible. D. The group determines how tasks are fulfilled by objects or interacting with other things. E. Responsibilities evolve into methods or operations.

In drawing the decision tree:

A. First, identify all conditions and actions and the order and timing of these (if they are critical). B. Second, begin building the tree from left to right while making sure you are complete in listing all possible alternatives before moving over to the right.

The data flow approach has (4) main advantages over the narrative explanation of the data movement. They are:

A. Freedom from committing to the technical implementation of the system too early B. Further understanding of the interrelationships of systems and subsystems C. Communicating current system knowledge to users through data flow diagrams D. Analysis of the proposed system to determine if all the data and processes have been defined

Data may be stored and retransmitted between Web pages using one of three methods:

A. In the U R L or location for the Web page. B. As a cookie or small file on the client or browser computer. Because there are limits to how many cookies a website may set, there must be some central control over who gets to set a cookie and the names used within the cookie. C. As a hidden field on a Web form.

A data repository is a large collection of project information. It includes:

A. Information about system data, including data flows, data stores, record structures, elements, entities, and messages B. Procedural logic and use cases C. Screen and report design D. Relationships between entries E. Project requirements and deliverables F. Project management information

Activity diagrams are not used for all use cases. Use an activity diagram when:

A. It helps to understand the activities of a use case B. The flow of control is complex C. There is a need to model workflow D. When all scenarios need to be shown

Physical data structures include elements and information necessary to design and implement the computer system. Additional elements on these structures include:

A. Key fields used to locate records. B. Codes to indicate record status. C. Codes to identify records when multiple record types exist on a single file. D. A count of how many entries are actually in a repeating group. E. Limits on the number of items in a repeating group. F. A password used by a customer accessing a secure website.

Use the following guidelines to develop a data flow diagram:

A. Make a list of business activities. B. Create the context level diagram, including all external entities and the major data flow to or from them. C. Create Diagram 0 by analyzing the major activities within the context process. Include the external entities and major data stores. D. Create a child diagram for each complex process on Diagram 0. Include local data stores and detailed processes.

Primitive process specifications are not created for:

A. Physical input and/or output processes B. Processes that represent simple data validation C. Processes for which pre-written code already exists

The data dictionary may be used for the following reasons:

A. Providing documentation B. Eliminating redundancy C. Validating the data flow diagram for completeness and accuracy D. Providing a starting point for developing screens and reports E. Determining the contents of data that is stored F. Developing the logic for data flow diagram processes G. Creating X M L (extensible markup language)

The goals of producing process specifications are:

A. Reduce process ambiguity B. Obtain a precise description of what is accomplished C. Validate the system design, including data flow diagrams and the data dictionary

The steps required to create a use case model are:

A. Review the business specifications and identify the actors within the problem domain B. Identify the high-level events and develop the primary use cases that describe the events and how actors initiate them C. Review each primary use case to determine possible variations of flow through the use case D. Develop the use case documents for all primary use cases and all important use case scenarios

The data dictionary may be used as a starting point when creating structured English as follows:

A. Sequenced (simple + between elements) data dictionary entries become simple structured English statements. B. Selection (elements within [ ] brackets) data dictionary entries become IF...THEN...ELSE structured English statements. C. Iteration (elements within { } braces) data dictionary entries become DO WHILE, DO UNTIL, or PERFORM UNTIL structured English statements.

Sequence diagrams illustrate a succession of interactions between either classes or objects over time. Sequence diagrams:

A. Show the starting object, either an actor or an interface, on the left B. Classes along the top of the diagram C. A vertical line indicating the time from when an object is created until it is destroyed D. A lateral bar showing when the class or object is busy doing things E. Horizontal arrows showing messages and optional parameters that are sent between classes F. The timing, with the first activities shown at the top of the diagram

Events fall into three categories:

A. Signals or asynchronous messages, where the calling program does not wait for a returning message. B. Synchronous messages, where the calling program waits for a returning message. C. Temporal events, which occur at a predestined time.

Process logic may be represented as:

A. Structured English B. A decision table C. A decision tree D. A formula E. Any combination of the above

Structured English is based on:

A. Structured logic, or instructions, organized into nested and grouped procedures B. Simple English statements such as add, multiply, move, and so on

A document type definition (D T D) is one way to define what is allowed in an X M L document, and can include:

A. The order of the elements B. If an X M L element is repeatable, and whether there must be at least one of the elements C. An optional element D. Definition of attributes

Sequence diagrams may be discussed using three layers:

A. The presentation layer, corresponding to the interface or boundary classes B. The business layer, containing the unique rules for the application, corresponding roughly to control classes C. The persistence or data access layer, for obtaining and storing data, corresponding to the entity classes

UML has three categories:

A. Things, the objects B. Relationships, the glue that holds things together C. Diagrams, categorized as either structure or behavioral

To select an appropriate structured decision analysis technique, systems analysts can refer to these guidelines:

A. Use structured English when there are many repetitious actions or when communication to end users is important B. Use decision tables when complex combinations of conditions, actions, and rules are found or you require a method that effectively avoids impossible situations, redundancies, and contradictions. C. Use decision trees when the sequence of conditions and actions is critical or when not every condition is relevant to every action (the branches are different).

Process descriptions may exist on a form or within a _ _ _ _ _______ ____________.

C A S E tool repository.

A _ _ _ _ matrix shows which programs or processes add, read, update, or delete master file records.

C R U D

_________, _________ __________, _________, _________, and _________ ________ must be known in order to design systems for structured decisions.

Conditions, condition alternatives, actions, action rules

_____ ___________ should be defined with descriptive information, length and type of data information, validation criteria, and default values.

Data elements:

The use of decision tables helps analysts ensure completeness and accuracy in analyzing structured decisions.

However, there are four main problems that can occur in developing decision tables. They are incompleteness, impossible situations, contradictions, and redundancy.

Unclear areas of a data flow diagram should be:

Noted and investigated

Process specifications are created for primitive processes and some higher level processes on a data flow diagram.

These are also called minispecs (mini specifications).

Method overloading is when:

a method may be defined more than once in a class, and used differently. The number of parameters or the type of parameter must be different.

Physical data flow diagrams include processes for _________, ___________, __________, and __________ records.

adding, reading, changing, and deleting. CRUD : Create Read Update Delete is an acronym for this.

Master or (transaction files)

are used to link all processes that operate at different times.

Each type of class has a special symbol:

called a stereotype, and extension to the U M L.

Structured English has advantages of:

clarifying the logic and relationships found in human languages, being an effective communication tool, and easy to teach and understand.

Class diagrams show:

classes and the relationships between classes.

Decision trees are used when:

complex branching occurs in a structured decision process. Trees are also useful when it is essential to keep a string of decisions in a particular sequence.

Data stores definitions:

contain descriptive information as well as physical characteristics. The name of the data structure found within the data store should be included.

Each message should be described in a

data dictionary

Data stores must be ___________,

defined, as they contain a minimal of all base elements as well as many derived elements.

Object-oriented systems:

describe entities as objects.

Each data flow should be defined with ____________ ____________ and its composite structure (elements).

descriptive information

Another approach used to create a data flow fragment is to analyze events, which are summarized in an _________ ________.

event table

Abstract classes are:

general classes or superclasses, and may not have any direct objects themselves. Only the specialized classes may create new objects.

Classes can:

inherit attributes and methods from other classes.

An interface data flow is data that is ________ or ________ from a child diagram that matches the parent diagram data flow.

input, output

A starting point in creating data dictionary entries is to analyze user ________ and ________ ________________.

input, output requirements.

The data dictionary:

is a reference work of data about data (metadata) compiled by systems analysts to guide them through analysis and design. It collects, coordinates, and confirms what a specific data term means to different people in the organization.

A method:

is an action that can be requested from any object of the class.

A message queue:

is an example of middleware used to transfer data between a server and mainframe.

An XML schema:

is another more precise way to define the content of an XML document.

A deferred event:

is one that is held until an object changes to a state that can handle the event.

Partitioning:

is the process of analyzing a data flow diagram and deriving a series of manual procedures and computer programs. A dashed line is drawn around a group of processes that are included in each computer program or manual procedure.

XML:

is used to share data between two different computer systems.

Polymorphism or method overriding:

is when a specialized class (or subclass) changes or overrides a method inherited from the general class (or superclass).

Data structures may be either __________ or __________.

logical, physical

Activity diagrams:

may be used to construct test plans.

An XML document:

may be used to define, filter, sort, and transform data.

A C R U D matrix:

may be used to help determine class methods.

Processes that do not create a child diagram are called ____________ ____________. Logic is written for these processes.

primitive process

Logical data structures:

reflect the mental model of how the users view the system.

Logical data flow diagrams:

show how the business operates and include processes that would exist regardless of the type of system implemented.

Communication (called collaboration in U M L 1.0) diagrams:

show how two or more things perform a behavior that an individual thing cannot do alone. They show the same information as a sequence diagram, but use numbers to indicate the order of the activities.

Statechart (or state transition) diagrams:

show the different states that an object may exist in and the events that cause an object to transition to a different state.

Generalization/specialization (gen/spec) diagrams:

show the relationship where a general class has specialized subclasses.

Activity diagrams may have:

states and events described in the repository.

The methods available for documenting and analyzing the logic of structured decisions include:

structured English, decision tables, and decision trees.

A use case model shows what:

the system does without describing how the system does it.

Creating a _____ ______ is another approach used to develop a data flow diagram. A _____ ______ shows the steps performed to accomplish a task.

use case

Data dictionary entries:

vary according to the level of the corresponding data flow diagram.

Activity diagrams are useful for:

viewing the overall activities of a use case and for dividing the project into various team members.

Through the use of (DFDs)

which emphasize the logic underlying the system, the systems analysts can put together a graphical representation of data movement through the organization