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System Analysis

System Analysis and Design. System Analysis. - Mr. Ahmad Al-Ghoul. Learning Objectives. Create a data dictionary entries for data flow Create a data dictionary entries for data stores Create a data dictionary entries for process Create a data dictionary entries for entities

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System Analysis

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  1. System Analysis and Design System Analysis - Mr. Ahmad Al-Ghoul

  2. Learning Objectives • Create a data dictionary entries for data flow • Create a data dictionary entries for data stores • Create a data dictionary entries for process • Create a data dictionary entries for entities • Describe a data dictionary reports • Describe where to use data dictionary System Analysis and Design System Analysis

  3. Data Dictionary • Data flows & Data storesData flows are paths along which data travels & Data stores are places where data is stored until needed. So we can say that Data flows are Data structures in motion & Data stores are Data structures at rest. System Analysis and Design System Analysis

  4. Data Dictionary • Documenting the data flow • Each data flow should be defined with descriptive information and it's composite structure or elements • Include the following information: • Data flow name or label: the data flow name as it appears on the DFD. • Alternate names: aliases for the DFD data flow names. • Description: describes the data flow and its purpose. • Origin: the DFD beginning, or source, for the data flow; the origin can be process, a data store, or an external entity • Distention: the DFD ending points for the data flow; the destination can be a process, a data store, or an external entity. System Analysis and Design System Analysis

  5. Data Dictionary • Documenting the data flow • Type: an indication of whether the data flow is a record entering or leaving file or a record containing a report, form, or screen. If the data flow contains data that are used between processes, it is designated as internal • Record: each data flow represent a group of related data elements called a record or data structure. • Volume and frequency: describes the expected number of occurrence for the data flow per unit of time, This could be records per day or any other unit of time • An area for further comments about the data flow System Analysis and Design System Analysis

  6. Data Dictionary [2] • Data Flow Example Name ORDER Description Contains customer order information and is used to update the customer master and item files and to produce an order record. Source CUSTOMER External Entity Destination Process 1.1, VERIFY ORDER Type Screen Data Structure Order Information Volume/Time 10/hour Comments An order record contains information for one customer order. The order may be received by mail, fax, or by telephone. System Analysis and Design System Analysis

  7. Data Dictionary • Data store • Data flow base elements are grouped together and a data store is created for each unique group • Data stores may be determined by analyzing data flows • Since a data flow may only show part of the collective data, called the user view, you may have to examine many different data flow structures to arrive at a complete data store description System Analysis and Design System Analysis

  8. Data Dictionary • Documenting the data store • Data store name or label : the data store name as it appears on the DFD, alternate names aliases for the DFD data store name • Description: describes the data store and its purpose. • Input data flows : the standard DFD names for the data flows interring the data store • Output data flows: the standard DFD names for the data flows leaving the data store. • Record: the record name in the data dictionary for the data store. • volume and frequency: describe the estimated number of records stored in the data store and how frequently they are updated System Analysis and Design System Analysis

  9. Data Dictionary • Documenting the Processes • Process name or label: the process name as it appears on the DFD • Description : a brief statement of the process general purpose • Process number: a reference number that identifies the process and indicates relationships among the various levels in the system • Input data flows: the standard DFD names for the data flows entering the process • Output data flows: the standard DFD names for the data flows leaving the process • Process description this section is filled only if the process is a functional primitive. For functional primitives the process description documents the processing steps and business logic System Analysis and Design System Analysis

  10. Data Dictionary • Documenting the Entities • By documenting all entities, the data dictionary can describe all external entities that interact with the system • Entity name: the entity name as it appears on the DFD. • Description: describe the entity and its purpose. • Alternate name(s): any aliases for the entity name. • Input data flows: the standard DFD names for the input data flows to the entity. • Output data flows: the standard DFD names for the data flows leaves the entity. System Analysis and Design System Analysis

  11. Data Dictionary • Data Dictionary Reports • A data dictionary is created when the system is developed, and is updated constantly as the system is implemented, operated, and maintained • Data dictionary documents the relationships among the system components • Many valuable reports can obtain from data dictionary including • An alphabetized list of all data elements by name • A report describing each data element and indicating the user or department that is responsible for data entry, updating, or deletion • A report of all data flows and data stores that use a particular data element • Detailed reports showing all characteristics of data elements, records, data flows, processes, or any other selected item stored in the data dictionary System Analysis and Design System Analysis

  12. Data Dictionary • Using the Data Dictionary • Data dictionaries may be used to • Create reports, screens, and forms • Generate computer program source code • Analyze the system design for completion and to detect design flaws System Analysis and Design System Analysis

  13. Sequence Summary • Data flows are paths along which data travels & Data stores are places where data is stored until needed. • Each data flow should be defined with descriptive information and it's composite structure or elements • Data flow base elements are grouped together and a data store is created for each unique group • By documenting all entities, the data dictionary can describe all external entities that interact with the system • Considering documentation in one location allows you to verify the information system’s accuracy and consistency more easily and generate a variety of useful reports System Analysis and Design System Analysis

  14. Sequence Summary • In this Sequence we have • Defined the terms data flow and data store • Explained how to create a data dictionary entries for data flow • Explained how to create a data dictionary entries for data stores • Explained how to create a data dictionary entries for process • Explained how to create a data dictionary entries for entities • Described a data dictionary reports • Described where to use data dictionary System Analysis and Design System Analysis

  15. Reference [1] System Analysis and Design, Sixth Edition Authors: Gary B. Shelly, Thomas J. Cashman and Harry J. Rosenblatt , Publisher: SHELLY CASHMAN SEWIES. [2] system analysis and design, sixth edition Authors: Kenneth E. Kendall and Julie E. Kendall Publisher: Prentice Hall [3] Modern Systems Analysis and Design Third Edition Authors: Jeffrey A. Hoffer , Joey F. George, Joseph S. Valacich Publisher: prentice hall [4] System Analysis and Design, 3rd Edition Authors: Dennis, Wixom, & Roth Publisher: John Wiley & sons System Analysis and Design System Analysis

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