The top-down approach to drawing data flow diagrams essentially involves moving “from the general to the specific” in terms of the detail level displayed (Kendall & Kendall, 2008, p. 220). Using information gathered from interviews, investigation, and personal observation, the systems analyst begins by developing a list of business activities. They then use the list to define the four elements of a data flow diagram, as follows:
§ External entities – send/receive data to/from the system
§ Data flows – the movement of data
§ Processes – the change or transformation of data
§ Data stores – a virtual storehouse where data can be added, examined, or retrieved
(Kendall & Kendall, 2008)
The analyst continues by creating a context diagram which only shows external entities and basic data flows into and out of the system. The context diagram contains a single process representing the whole system (Kendall & Kendall, 2008).
The analyst then draws Diagram 0, which is the next lower level from the context diagram. Diagram 0 “explodes” the context level diagram, providing a closer, more detailed view of the system. It typically includes three to nine processes and shows the major data stores which represent master files. At Diagram 0, inputs and outputs relative to the context level diagram remain unchanged but the data flows expand to lower levels with increased detail (Kendall & Kendall, 2008).
At this point the analyst proceeds to explode Diagram 0, adding a more detailed child diagram for each of Diagram 0’s processes. Each exploded Diagram 0 process is called a parent process, and the resultant diagram is called a child diagram. Past Diagram 0, entities are generally not shown (Kendall & Kendall, 2008).
There must be ...
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...es successively more detailed diagrams. The diagrams progress from the basic, context level diagram, to the more detailed Diagram 0, to the even more detailed child diagrams which branch from Diagram 0’s parent processes.
The analyst must check their child diagrams for errors, particularly to avoid creating unbalanced conditions where there are input and/or outputs which do not appear on the corresponding parent diagrams. The diagram progresses to a further level of detail, moving from a logical to a physical data flow diagram. Finally, the analyst partitions the physical diagram, creating groups of automated processes which will become programs, or, separating processes which for various reasons cannot or should not be grouped together.
Works Cited
Kendall, K. & Kendall, J. (2008). Systems Analysis and Design. Upper Saddle River, NJ: Pearson Custom Publishing.
The six stages that Kohlberg defines are grouped into three levels, with two levels at each stage. They are grouped as follows:
Stage 3 involves creating an Architectural Model version of the whole system including sub systems. A Viewpoint Hierarchy shows a skeleton version of the system which can be ins...
Process: Divides the acquisition life cycle into a five phase process where program health is reviewed during Decisions Events.
Specifically what my main goal in this paper is to help you understand what a Computer Systems Analyst is, what they do, things like those that explain everything about a Computer Systems Analyst. You could probably guess from the name of this job title that the main function of a Computer Systems Analyst is to determine how a computer system can best help something. Well this is exactly the key role of what they do is determine how a computer system can best serve a business or organization's needs. David P. Bieg says “You need to understand how systems interact, but you don’t really need to understand the core of every technology---it’s really about how information and process flows through the system.” Someone who is working as a Computer Systems Analyst is going to to have to be big-picture oriented and be able to understa...
In stage three, concrete operational, the child now rationalises logically about concrete, real experiences. They have the ability to mentally reverse actions and are able to focus simultaneously on different features of a problem.
A flowchart is a planning tool that uses graphics or symbols to illustrate the steps of a particular process. In a business organization "flowcharting, also known as logic or flow diagramming, is an invaluable tool for understanding the inner workings of, and relation- ships between, business processes." (Harrington, 86) There are four basic flowcharts, each having a specific function and they include: block diagrams, ANSI standard flowchart, functional flowchart, and geographical flowchart. Understanding and applying flowcharts normally will improve the quality of a company's product or service.
After the systems planning is complete, the next course of action is the systems analysis phase. This phase includes defining the requirements of the system. This means that the team must conclude what the system needs to do in order to satisfy the users. This is done by forming a requirements...
The boundaries may seem obvious to you, but once a project team starts talking about where the process begins and ends, you will appreciate the clarity the SDD brings to the work.
This is where the question “what if” is asked. It is the level where deeper level thinking is required. Connections between all the analyses are made and grouped together. Everything/all the steps come together to make up the extend level. The previous information is gathered to help form connections and think deeper on the topic. It explains distinctions and relationships, and it also shows understanding of the other stages as well. With this stage another problem or question could generate from the information provided causing the stages to start over again. The human knot caused the class to us communication skills to unravel it. Combing all the stages together to get to the extend stage means that we had to first see how everyone was tied together and then figure out different strategies to get out of it. Communication became the biggest help because it heled us understand and identify the answer/strategy to get out.
Multiview looks at the human activity within the organisation and analyses it in order to determine a problem theme. Using diagrams to give an overview of human activity within departments make it easier for users to pinpoint discrepancies with workflows. Once identified, users of the system can assist the developers to make the necessary changes that will increase efficiency with human activity.
[1]- Ralph Stair, George Reynolds and Thomas Chesney. 2012. Fundamentals of Business information systems. 2nd edition: Cengage Learning EMEA.
As part of developing the need in the initial investigation step in the systems development life cycles (SDLC) process, a constructive method is use case. Use case is a technique for capturing requirements with written scenarios in non-technical terminology that describe how a system interacts with a user or another system (University of Phoenix, Course Syllabus, 2006). There are two fundamental pieces, along with how they relate, to bear in mind: the actors and the goals. The actors are everyone and everything that will use (or be used) by the project progress reports, and the goals, which are what the actors want to achieve. The use case will describe the goals achieved by the actors who perform tasks (Carr & Meehan, 2005).
... different layers such as ETL stage, SIF, BDW and how data is processed to generate reports according to the requirement. The processing of information from raw data to different processing stages culminating in coherent information is fascinating.
There are different types of UML diagrams. Each UML diagram is designed to let developers and customers view a software system from a different perspective and in varying degrees of abstraction. UML diagrams commonly created in visual modeling tools include: use case diagram which displays the relationship among actors and use cases. Class case diagram models class structure and contents using design elements such as classes, packages and objects. It also displays relationships such as containment, inheritance, associations and others. Sequence diagram displays the time sequence of the objects participation in the interaction. This consists of the vertical dimension (time) and horizontal dimension (different objects). Collaboration diagram displays an interaction organized around the objects and their links to one another. Numbers are used to show the sequence of messages. State diagram displays the sequences of states that an object of an interaction goes through during its life response to received stimuli, together with its response and actions. Activity diagram displays a special state diagram where most of the states are action states and most of the transitions are triggered by completion of the actions in the source states. This diagram focuses on flows driven by internal processing.
Within the analysis phase a set of goals are needed within the domain. From this there are three perspectives which are taken; the object model the Ronald LeRoi Burback (1998) states “dynamic model, and a functional model. The object model represents the artifacts of the system. The dynamic model represents the interaction between these artifacts represented as events, states, and transitions. The functional model represents the methods of the system from the perspective of data flow.” After the analysis phase the system design phase takes place. Here the system is sub-categorized and appointed tasks and persistent data storage is established, also within this phase the architecture is formed. Lastly the object design phase starts and is where the implementation plan is established and algorithms and object classes are also