IM 341 Exam #2

Data Flow

A single system is represented on a context diagram and it provides the scope of the system being represented because it shows the system boundaries. The diagram shows only the major information flows between the system and the external parties that interact with the system. The context diagram shows one process (representing the entire system) labeled with a 0

Flowchart Symbols: Line with a note

Annotation: This symbol is used to include important supplementary information or explanations that are difficult to describe graphically within the flowchart itself. Rather than using a Communication Link Symbol (show below), in this class, we will use annotations to note electronic inputs or outputs (such as an electronic data update flow to another system or to a customer). Annotations should also be used to denote timing (e.g., suspended action steps) or critical controls within a process.

Flowchart Symbols: Skinny Square

Auxiliary operation symbol used to denote functions performed by devices other than computers (or human, manual processing).

Information Processes

Circles or rectangles with rounded corners are used to represent this. Takes data inflows and transform them to information outflows to be distributed or stored. The symbol contains two labels.

Flowchart Symbols: Zig-Zag arrow

Communication Link Symbol: Some flowcharts use this symbol to represent when electronic channels such as the Internet, telephone lines, radio waves, or satellite transmitters, are used to transfer data.

DFD Symbol: Parallel Lines or a Square without the right side

Data Stores. Used to denote stored data that is at "rest"

Flowchart Symbols: Side Square (Diamond)

Decision points: Sometimes in a system, the course the of action depends on making a decision or choice. For example, if a clerk's task is to review a document for completeness, the next action would depend on deciding whether the document is complete. Suppose that if the document is complete, the clerk files the document. On the other hand, if the document is incomplete, the clerk sends the document back to the user department. A decision symbol would display the decision, and a description of the decision would appear in the symbol (e.g. "Is the document complete?"). Two labeled flow lines would exit from the decision symbol to illustrate the indicated course of action. In this case, a line labeled with "yes" ("yes" the document is complete) would lead to a paper off‐line file, while a line labeled "no" ("no" the document is not complete) would show the document flowing back to the user department. All decision symbols must have at least two labeled flow lines coming from the decision point.

Flowchart Symbols: Rhombus

I/O Symbol:The Input/Output symbol is typically used to display records and master files on a program logic flowchart. It is also used to denote records and files (journals and ledgers) in a manual flowchart

DFD Symbol: Circle

Information Process. Must use a verb to label this. Labeled with a number and word.

Flowchart Symbols: Goldfish Symbol

Input and Output: The document symbol is used for all types of paper source documents that are processed by the system (e.g. checks, invoices, ledgers, journals, and reports). The symbol is labeled with a document name and document copy number

Flowchart Symbols: Upwards Slanted Rectangle

Input: On‐line Computer Device (Keyboard Input and Terminal Display): This symbol is used to describe the entry of data into a computer through an on‐line terminal/keyboard (keyboard input).

Flowchart Symbols: Football Shape

Input: On‐line Computer Device (Keyboard Input and Terminal Display): This symbol is used to show a computer‐terminal display

Flowchart Symbols: Connected Slanted Rectangle and Football Shape

Input: On‐line Computer Device: In some cases, the computer terminal display is used in conjunction with the on‐line computer‐device (keyboard) symbol to show data being entered into a computer process using an on‐ line terminal.

Flowchart Symbols: Tall Rectangle with a point in bottom right corner

Input: Transmittal Tape: In some flowcharts, the transmittal tape is used to show manually prepared control totals that are used compare to totals generated by computers.

Black Hole

No process can only have inputs. Must be a Sink

Flowchart Symbols: Square with a Upside-down triangle. (Shape + Step #1 , Page 4

Off Page Connector: Off page connectors are used to connect multiple pages of a document flowchart. This symbol would be placed on page 2, and directs the reader to look at Page 4 for the symbol that continues step 1.

Flowchart Symbols: Small Circle

On-Page Connector: On‐page connectors tell the user where to go next when the flow continues on the same page. A letter or number is added to the symbol. Each connector must be paired with a connector containing a matching number (or letter) located on the SAME page. Use different letters or numbers for each set on the same page.

Flowchart Symbols: Square with an X

Physical (Non‐document) Objects: In some cases (depending on the type of flowchart and preferences of the client) you will use this symbol to denote any physical object that may accompany a data flow (e.g., merchandise, supplies, and products). Reminder - DO NOT represent goods flow on a DFD.

Flowchart Symbols: Rectangle

Processing: Machine‐processing symbol for on‐line computer processing. This typically denotes a computer application (such as an order entry program or an invoicing program).

Flowchart Symbols: Upside-down Trapezoid

Processing: The manual‐process symbol indicates a manual operation (such as completing forms or verifying amounts). Paper documents are a common input to the manual process and paper documents are common outputs from the process

DFD Symbol: Square

Source/Sink. Must use a noun to label this. (e.g. Customer, Vendors, Government Agency, and other systems)

Sink

Squares represent the origin destination of an information outflow. external to (i.e. outside the scope of) the system represented on the diagram. They delineate the system boundaries.

Source

Squares represent the origin of a data inflow. external to (i.e. outside the scope of) the system represented on the diagram. They delineate the system boundaries.

Flowchart Symbols: Upside-Down Triangle with a letter for temporary Upside-Down Triangle with a letter for temporary and a horizontal line on top of the letter

Storage (origin and destination files): A manual system off‐line storage symbol represents any storage of paper documents (e.g., file cabinet, safe, or shelves). Two types of files exist ‐ temporary and permanent

Flowchart Symbols: Upside Cylinder

Storage (origin and destination files): Computer-storage: Disk file symbol. A file label is included on the symbol.

Flowchart Symbols: Sideways Cylinder

Storage (origin and destination files): Computer‐storage: Direct storage (Disk). A file label is included on the symbol.

Flowchart Symbols: Message Bubble Shae

Storage (origin and destination files): Computer‐storage: Sequential file (tape) symbol. A file label is included on the symbol.

Flowchart Symbols: rectangle being blown left shape

Storage (origin and destination files): Computer‐storage: Visio calls this an External data symbol. It is intended to be used as a general purpose data storage shape that does not indicate how or where the data is stored. A file label is included on the symbol.

Flowchart Symbols: Small rounded rectangle

Terminal or System Entry/Exit: This symbol is used to indicate the beginning, or ending point of the process represented on a flowchart. It is also used to display system entry or exit of data. The label in the terminal symbol often describes the activity (trigger) that begins/ends the flowchart segment, or it displays the outside6 source or destination of data.

Context Diagram

The least detailed level of data flow diagramming.

Level 1, 2, 3 etc. DFD

Theses are more complex DFD's than a level 0 DFD. These DFD's go into the detail of each information process, such as 1.1 1.2 1.3 (This is a evel 3 DFD) 3.1.1. , 3.1.2. , 3.1.3 , 3.1.4. (This is a level 4 DFD)

Verify, Access, Compare, Receive

What are words for inputs?

Update, Generate, Sent, Stored, Filed

What are words for outputs?

Primitive DFD

When you have decomposed the system processes into the most detailed levels (referred to as the lowest level DFDs), the resulting DFDs are called __________ DFDs

Decomposition

When you take the processes shown on a data flow diagram and divide each into more detailed (sub)processes

UML (Unified Modeling Language)

a standardized notation for modeling of real‐world objects. Professionals use this to complete business modeling (including architectural and application modeling, as well as system development, deployment, maintenance, and evolution)

DFD Symbol: Directional Arrows

display the route of data inflow and outflow (data that is moving from one place to another). They can be straight or curved. generally labeled with the name of the data (e.g. a customer order, a bill, a financial analysis)

Level 0 DFD

divided into the more detailed processes performed within the system to create a ________. The key differences between this DFD and the context diagram include 1) the single process is broken down into major process steps that use the input and output from the sources and sinks shown on the context diagram, and 2) data stores are added to the details shown

Document Flowcharts

focus on the creation, flow, and destinations of documents and information within a system

Balancing

helps you check for internal consistency of your DFD levels because when you balance a DFD it means you preserve the inputs and outputs of a parent DFD at the next level of decomposition (i.e., the inputs and outputs from a higher level process should show up on the lower level DFD)

Systems Flowcharts

more comprehensive flowcharts. They show the entire system configuration, including the data inputs, data outputs, and processes of a system, and the relationships between system inputs, processes and outputs

Flowcharts

popular tool for systems auditors. Unlike DFDs, this focuses on the physical aspects of information flows, files, sources, destinations and processes

Program Flowcharts

shows the logic and processing steps of a computer program or code.

Flowchart Symbols: Lines with Arrows

shows the origination points or destinations of inputs and outputs. Can be bidirectional unlike DFDs. Do not label these unless they are for annotations

Data Flow Diagram (DFD)

used for a variety of system analysis purposes, including graphically displaying the movement of data through a process (between entities external to a system and any processes and data stores within a system). DISREGARD physical attributes of a system such as organizational units, the computer on which the data are processed, and the media on which the data are stored. The movement of data across offices or departments within a particular system environment is NOT represented

Data Store

used to denote stored data, and are necessary any time is stored ("at rest"). When output from one process "rests" before it is used as input to a second process, a data store symbol is necessary