Structured Analysis Lec 2 - Structured Systems Analysis:...

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Unformatted text preview: Structured Systems Analysis: Structured Systems Analysis: Guidelines for Guidelines for onstructing DFDs and onstructing DFDs and Constructing DFDs and Constructing DFDs and Data Dictionaries Data Dictionaries EGA/ERLJ IE 154 Objectives for Today r Know naming conventions for DFDs r Know the guidelines for constructing DFDs r Define the elements of the Data Dictionary now the two conventions for describing r Know the two conventions for describing the Data Dictionary r Solve Example Naming Data Flows r The data flow name must be descriptive of the information it carries. The name must apply to its major components. r In a given DFD, data flow names must be unique r The name is made up of glossary keywords and class keyword symbols which are concatenated using hyphens (-) Glossary Keywords r Are shortened or abbreviated keywords. The abbreviation should be from two to five characters long. The glossary keywords, together with the full keywords are maintained in the keyword glossary. r Example Abbreviation Keyword c ACCT ACCOUNT c ADDR ADDRESS c CUST CUSTOMER c … Class Keywords r Are single character codes of the main classes of elemental data items. Class keyword symbols when used, are always appended to the primary name. r Example Keyword Symbol c Number N c Name M c Code C c Quantity (Count) Q c Amount (Money) A c Date D Class Keywords r Example cont. c Keyword Symbol c Text T c Constant K c Percent P c Flag F c Switch S Examples for Data Flows r CUST-ACCT-N r CUST-M r CUST-SHIP-D r CUST-INVC-ADDR-T r CUST-BORDR-PROD-Q r SALES-BRNCH-C r PROD-UNIT-PRICE-A r DSCNT-RATE-P Naming Data Stores r The data store name must be descriptive of the information in stores c WIDGET INVENTORY c PURCHASE ORDERS c STUDENT RECORDS Naming Processes r The process name should be concise, meaningful and consistent with the actual function of the process. Process names must consist of one rb (preferably a strong action verb (preferably a strong action verb) in the imperative mode and one object. A process should be named in terms of its inflows and outflows. r Avoid name processes using verbs like “process” and “handle” Naming Processes r Example c Process Sales Order r Convert Sales Order to Purchase Order c Handle Document r Transport Document to Logistics Numbering and Labeling Convention r Context Diagram c The context diagram is labeled “Context Diagram” c The context bubble is numbered 0. r Top Level Diagram c The top-level diagram is labeled Diagram 0 c Each process bubble is numbered from 1 to as many bubbles exploded from the context bubble but not exceeding 7. Numbering and Labeling Convention r Middle and Bottom-Level Diagrams c Each Middle or bottom level diagram is labeled with the process bubble number it was leveled from (the arent bubble) and the parent parent bubble) and the parent bubble’s name....
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This note was uploaded on 05/19/2011 for the course IE 2 taught by Professor A during the Spring '11 term at University of the Philippines Diliman.

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Structured Analysis Lec 2 - Structured Systems Analysis:...

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