MANAGING DATA RESOURCES

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CHAPTER-7 MANAGING DATA RESOURCES
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SOME DEFINITIONS
ENTITYTHINGS ABOUT WHICH INFORMATION IS
COLLECTED AND STORED. EX. A PERSON,
PRODUCTSATTRIBUTESCHARACTERISTIC THAT DESCRIBE
AN ENTITYEX. PRODUCT NUMBER, SOCIAL SECURITY
NUMBER FIELDA GROUP OF CHARACTER, OR A GROUP
OF WORDS OR A NUMBER
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SOME DEFINITIONS
RECORDSUBSETS OF DATA ON A PARTICULAR ENTITY, A
GROUP OF FIELDS THAT HAVE A KEYFIELD WHICH
UNIQUELY IDENTIFIES THE RECORD FILEA GROUP OF
RECORDS WITH SOME COMMONALITY DATABASEA GROUP
OF FILES THAT ARE RELATED
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HIERARCHY OF DATA IN A COMPUTER SYSTEM

• DATABASE
• FILE
• RECORD
• FIELD
• BYTE
• BIT

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FILES THE TRADITIONAL APPROACH
TWO WAYS TO STORE DATA

• SEQUENTIAL FILE ORGANIZATION
• RECORDS ARE ACCESSED SEQUENTIALLY. I.E. IN THE
  SAME ORDER THEY ARE STORED
• ONLY FILE ORGANIZATION THAT CAN BE USED ON
  MAGNETIC TAPE

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FILES THE TRADITIONAL APPROACH
TWO WAYS TO STORE DATA

• DIRECT OR RANDOM FILE ORGANIZATION
• RECORDS CAN BE ACCESSED DIRECTLY
• IS UTILIZED WITH MAGNETIC DISKS

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PROBLEMS WITH THE TRADITIONAL APPROACH
WITH THE TRADITIONAL APPROACH EACH FUNCTIONAL
AREA AND GROUP IN THE ORGANIZATION MAY MAINTAIN
ITS OWN FILES INDEPENDENTLYAND THEREFORE, THE
FOLLOWING PROBLEMS CAN OCCUR
DATA REDUNDANCY AND INCONSISTENCY
INFLEXIBILITY POOR SECURITY LACK OF DATA
SHARING AND AVAILABILITY PROGRAM-DATA DEPENDENCE
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DATABASES THE MODERN APPROACH
A DATABASE IS A SUPERSET OF RELATED FILES IN
WHICH DATA ARE INTEGRATED AND RELATED SUCH THAT A
SOFTWARE PROGRAM CAN PROVIDE ACCESS TO ALL THE
DATA. IN A DATABASE THE DATA IS CENTERALIZED
AND DATA REDUNDANCY IS MINIMIZED.
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DATABASE MANAGEMENT SYSTEM (DBMS)
IS THE SOFTWARE THAT PROVIDES ACCESS TO THE
DATABASE. IT IS THE INTERFACE BETWEEN THE
APPLICATION PROGRAMS AND THE DATA FILES.
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DATABASE MANAGEMENT SYSTEM (DBMS)
IS THE SOFTWARE THAT PROVIDES ACCESS TO THE
DATABASE. IT IS THE INTERFACE BETWEEN THE
APPLICATION PROGRAMS AND THE DATA FILES.
DBMS HAS THREE COMPONENTS
DATA DEFINITION LANGUAGE (DDL)DEFINES EACH DATA
ELEMENT AS IT APPEARS IN THE DATABASE.
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DATABASE MANAGEMENT SYSTEM (DBMS)
DBMS HAS THREE COMPONENTS
DATA MANIPULATION LANGUAGE (DML)USED BY ENDUSERS
AND PROGRAMMERS TO MANIPULATE DATA IN THE
DATABASE. DML CAN INTERFACE WITH HIGH PROGRAMMING
LANGUAGES. THIS ENABLES THE PROGRAMMER TO PERFORM
ADDITIONAL DATA MANIPULATION THAT THE DML DOES
NOT ALLOW.
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DATABASE MANAGEMENT SYSTEM (DBMS)
DBMS HAS THREE COMPONENTS
DATA DICTIONARYA COMPREHENSIVE LIST THAT GIVES
THE FORM, FUNCTION, MEANING, AND SYTAX OF THE
DATA IN THE DATABASE. DATA DICTIONARY MAY CONTAIN
A SECURITY FUNCTION I.E. WHICH FILES CAN BE
ACCESSED, CHANGED, OR MODIFIED BY SPECIFIC USERS.
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LOGICAL VS. PHYSICAL VIEWS OF DATA
LOGICAL VIEWREFERS TO THE WAY THE USER VIEWS THE
DATA  PHYSICAL VIEWREFERS THE WAY THE DATA
ARE PHYSICALLY STORED AND PROCESSED
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LOGICAL DATABASE MODELS
1. HIERARCHICAL MODEL 2. NETWORK
MODEL 3. RELATIONAL MODEL
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ADVANTAGES AND DISADVANTAGES OF DIFFERENT
DATABASE MODELS
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ADVANTAGES AND DISADVANTAGES OF DIFFERENT
DATABASE MODELS
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NEW DATABASE TRENDS
DISTRIBUTED DATABASEA DATABASE THAT IS NOT
CENTERALIZED AND IS LOCATED IN MORE THAN ONE
LOCATION. TWO TYPES OF DIATRIBUTED
DATABASEARE PARTITIONED DATABASE REPLICATED
DATABASE
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NEW DATABASE TRENDS
OBJECTED-ORIENTED DATABASESTORES DATA AND
PROCEDURES AS OBJECTS. SUITABLE FOR MULTIMEDIA
ENVIRONMENT HYPERMEDIA DATABASEORGANIZES DATA
AS A NETWORK OF NODES LINKED IN ANY PATTERN
ESTABLISHED BY THE USER. THE NODES CAN CONTAIN
TEXT, GRAPHICS, AND VIDEO.
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MULTIDIMENTIONAL DATA ANALYSISALLOWS FOR
MANIPULATING AND ANALYZING DATA FROM DIFFERENT
PERSPECTIVES
DATA WAREHOUSESA DATABASE THAT HAS REPROTING AND
QUERY TOOLS AND CAN STORE CURRENT AND HISTORICAL
DATA EXTRACTED FROM VARIOUS OPERATIONAL SYSTEMS
AND CAN CONSOLIDATE IT FOR MANAGEMENT REPORTING
AND ANALYSIS.
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LINKING DATABASES TO THE WEBSOFTWARE HAS BEEN
DEVELOPED THAT ALLOWS ACCESS TO OLD DATABASES
THROUGH WEB. IT IS EASY AND COST EFFICIENT
COMPARED TO DESIGNING A NEW DATABASE.
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MANAGERIAL AND ORGANIZATIONAL REQUIREMENTS FOR
CREATING A DATABASE ENVIRONMENT
DATA ADMINISTRATIONHOW TO MANAGE DATA
RESOURCES, DEVELOP INFORMATION POLICY, DATA
PLANNING, DATA MAINTENANCE, AND DATA QUALITY
STANDARDS
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MANAGERIAL AND ORGANIZATIONAL REQUIREMENTS FOR
CREATING A DATABASE ENVIRONMENT
DATA PLANNING AND MODELING METHODDEVELOP A PLAN
THAT ADDRESSES THE INFORMATION REQUIRMENT OF THE
WHOLE ORGANIZATION RATHER THAN A PARTICULAR
SEGMENT
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MANAGERIAL AND ORGANIZATIONAL REQUIREMENTS FOR
CREATING A DATABASE ENVIRONMENT
DATABASE TECHNOLOGY AND MANAGEMENTASSIGN A
DATABASE MANAGER WHO IS RESPONSIBLE FOR TECHNICAL
AND OPERATIONAL ASPECTS OF MANAGING DATA I.E.
DEFINING DATABASE STRUCTURE, SECURITY PROCEDURES,
DOCUMENTATION AND MAINTENANCE
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MANAGERIAL AND ORGANIZATIONAL REQUIREMENTS FOR
CREATING A DATABASE ENVIRONMENT
DATABASE USERSDATABASE DESIGN TEAM MUST WORK
CLOSELY WITH USERS TO CREATE THE PHYSICAL
DATABASE, THE LOGICAL RELATIONS, AND THE ACCESS
RULES AND PROCEDURES