INTRODUCTION
INTRODUCTION
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What is Database?
A necessity for almost any enterprise to carry out its business. Consists of raw facts, and when organized may be transformed into information
A collection of data organized to meet users’ needs
Database management system (DBMS)
A group of programs that manipulate the database and provide an interface between the database and the user of the database or other application programs
Information and Organizations
DBMS ‘Discussion’
A collection of programs that enables you to store, modify, and
extract information from a database. There are many different types
of DBMSs, ranging from small systems that run on personal
computers to huge systems that run on mainframes. The following
are examples of database applications:
computerized library systems
automated teller machines
flight reservation systems
computerized parts inventory systems
From a technical standpoint, DBMSs can differ widely. The terms
Information and Organizations
Hierarchy of data
Characters
Personel file
Department file
Payroll file
(Project database)
005-10-6321 Johns Francine 10-7-65
549-77-1001 2-17-79
098-40-1370 1-5-85
(Personnel file)
098-40-1370 1-5-85 598
(Record containing SSN, last name, first name, date of hire)
(Last name field)
(Letter ‘F’ in ASCII)
Information and Organizations
Terminology
A collection of integrated and related files
A collection of related records
A collection of related fields
A group of characters
Basic building block of information, represented by a byte
Information and Organizations
Data Entities, Attributes, and Keys
A generalized class of people, places, or things (objects) for which data are collected, stored, and maintained
E.g., Customer, Employee
A characteristic of an entity; something the entity is identified by
E.g., Customer name, Employee name
A field or set of fields in a record that is used to identify the record
E.g, A field or set of fields that uniquely identifies the record
Information and Organizations
Keys and Attributes
Attributes (fields)
Employee # Last name First name Hire date Dept. #
005-10-6321 Johns Francine 10-7-65 257
549-77-1001 2-17-79 650
098-40-1370 1-5-85 598
Information and Organizations
Advantages
Reduced data redundancy
Easier modification and updating
Better access to data and information
Better overall protection of the data
Shared data and information resources
Information and Organizations
Disadvantages
Relatively high cost of purchasing and operating a DBMS in a mainframe operating environment
Increased cost of specialized staff
Increased vulnerability
Information and Organizations
Class Exercises
1) What is the difference between Data and Database.
2) What is the purpose of DBMS
3) List 2 advantages of Database
4) List 2 disadvantages of Database
5) List some examples of attributes
Information and Organizations
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