Lecture 10 - Database Design - Database Concepts EEE 13...

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Database Concepts EEE 13 Department of Electrical and Electronics Engineering
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Database Management for Strategic Advantage We live in the Information Age Information used to make organizations more productive and competitive Databases used to support business operations
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Databases Before the Use of Computers Data kept in books, ledgers, card files, folders, and file cabinets Long response time Labor-intensive Often incomplete or inaccurate
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Design Objectives Purposeful information retrieval Efficient data storage Data availability Efficient updating and retrieval Data integrity Data storage is considered by some to be the heart of an information system.
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Two Approaches to Data Storage A file is a collection of similar records Examples of individual files, each unique to a particular application – SALES-FILE – CURRENT-ACTIVITY-FILE – PERSONNEL-FILE A database is a collection of interrelated files Centrally controlled store of data intended for use in many different applications
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Conventional Files CURRENT-ACTIVITY-FILE NUM NAME AREA 2001 PERSONNEL-FILE NUM DEPT NAME ADDRESS PHONE HIRED SALARY TITLE SALES-FILE NUM NAME 1998 1999 2000
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The Database The database approach allows different users to share the same database yet access different data sets Database Data Set 2 Data Set 1 Data Set 3
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The Database It is a central source of data that is meant to be shared by many users for a variety of applications It is not merely a collection of files DBMS is the heart of a database – Allows creation, modification, and updating of the database – Retrieval of data – Generation of reports
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Goals of Database Design Efficient – provide for the efficient storage, update, and retrieval of data Reliable – high integrity to promote user trust in the system and the data Adaptive – adaptable and scalable to new and unforeseen requirements and applications The prerequisite for database design is a logical data model, fully attributed and n ormalized e ntity r elationship d iagram.
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The Database Approach Advantages Data sharing means that data are stored only once Promotes data integrity – Changes to data are accomplished more easily and reliably Flexible in accommodating future user needs Disadvantages All data are stored in one place – Data are more vulnerable to disaster – Requires complete backup Time and cost constraints
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Key Database Issues and Activities Entering Data Querying Data Creating Reports
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