HRM 3440 Lecture Notes - Lecture 36: Data Flow Diagram, Requirements Analysis, Data Element
23 May 2018
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HRM 3440 Lecture 36 Notes – Requirements Analysis
Introduction
• A system modeled with a DFD could operate manually or could be computer based
• If computer based, the system could operate with a variety of technologies.
• DFDs are easy to develop and easily understood by nontechnical people.
• Data-flow diagrams use four primary symbols.
• Data flow.
• The data-flow line includes arrows that show the direction of data element movement.
• Process symbol.
• The process symbol reveals a function that is performed.
• Computing gross pay, entering a sales order, delivering merchandise, and printing a
report are examples of functions that can be represented with a process symbol.
• Entity symbol.
• The entity symbol shows either the source or destination of the data element.
• An entity can be, for example, a customer who initiates a sales order, an employee who
receives a paycheck, or a manager who receives a financial report.
• Data store.
• A data store reveals a storage location for data.
• A data store is any computerized or manual data storage location, including magnetic
tape, disks, a filing cabinet, or a desk.
• Comparing entity-relationship diagrams with data-flow diagrams provides insight into
the concept of top-down design.
• An entity-relationship diagram and a data-flow diagram for the same business
relationship—namely, a member of a golf club playing golf.
• The overall purpose of requirements analysis is to determine user, stakeholder, and
organizational needs.
• For an accounts payable application, the stakeholders could include suppliers and
members of the purchasing department.
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