COURSE TITLE: INTERNATIONAL BUSINESS                              COURSE CODE: BUS-303                                    ...
HISTORYDATABASES HAVE BEEN IN USE SINCE THE EARLIEST DAYS OF ELECTRONIC COMPUTING. UNLIKE MODERN SYSTEMSWHICH CAN BE APPLI...
IN THIS PAPER, HE DESCRIBED A NEW SYSTEM FOR STORING AND WORKING WITH LARGE DATABASES. INSTEAD OFRECORDS BEING STORED IN S...
RELEASED IN 1978.STONEBRAKER WENT ON TO APPLY THE LESSONS FROM INGRES TO DEVELOP A NEW DATABASE, POSTGRES, W HICHIS NOW KN...
A HIERARCHY OF SEVERAL LEVELS OF DATA HAS BEEN DEVISED THAT DIFFERENTIATES BETWEEN DIFFERENTGROUPINGS, OR ELEMENTS, OF DAT...
• SHARING OF DATA AND MULTI USER TRANSACTION PROCESSINGDEFINITION OF DBMS:A DATABASE MANAGEMENT SYSTEM (DBMS) IS THE COMBI...
MANNER WITH NO REDUNDANCY, FOR EXAMPLE ROLL NUMBER IN A CLASS IS NON-REDUNDANT FORM AND SOTHESE HAVE UNIQUE RESISTANCE, BU...
• DATA DEFINITION: THE DBMS MUST BE ABLE TO ACCEPT DATA DEFINITIONS (EXTERNAL SCHEMAS, THECONCEPTUAL SCHEMA, THE INTERNAL ...
IN TRADITIONAL FILE PROCESSING, EVERY USER GROUP MAINTAINS ITS OWN FILES. EACH GROUP INDEPENDENTLYKEEPS FILES ON THEIR DB ...
BY USING DATABASE SYSTEM, STANDARD CAN BE MAINTAINED IN AN ORGANIZATION. DBA IS OVERALLCONTROLLER OF DATABASE SYSTEM. DATA...
DATABASE MANAGEMENT SYSTEM HAS MANY ADVANTAGES, BUT DUE TO SOME MAJOR PROBLEM ARISE IN USINGTHE DBMS, IT HAS SOME DISADVAN...
CENTRALIZING ALL DATA OF AN ENTERPRISE IN ONE DATABASE MAY MEAN THAT THE DATABASE BECOMES ANINDISPENSABLE RESOURCE. THE SU...
Arif
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  1. 1. COURSE TITLE: INTERNATIONAL BUSINESS COURSE CODE: BUS-303 PROGRAM: BBA SUBMITTED TO: MD.SAHADAT HOSSAIN LECTURER IN MANAGEMENT SCHOOL OF BUSINESS ADMINISTRATION BANGLADESH UNIVERSITY OF BUSINESS & TECHNOLOGY (BUBT). SUBMITTED BY: GROUP NAME: INNOVATIVE GROUP MEMBERS: NAME ID SECTION INTAKEARIF HOSEN 10111101217 05 23NDMOUIY AKTER 10111101185 05 23ND 10111101189 05 23ND BANGLADESH UNIVERSITY OF BUSINESS & TECHNOLOGY (BUBT). COMMERCE COLLEGE ROAD, MIRPUR-02, DHAKA-1216.
  2. 2. HISTORYDATABASES HAVE BEEN IN USE SINCE THE EARLIEST DAYS OF ELECTRONIC COMPUTING. UNLIKE MODERN SYSTEMSWHICH CAN BE APPLIED TO WIDELY DIFFERENT DATABASES AND NEEDS, THE VAST MAJORITY OF OLDER SYSTEMSWERE TIGHTLY LINKED TO THE CUSTOM DATABASES IN ORDER TO GAIN SPEED AT THE EXPENSE OF FLEXIBILITY.ORIGINALLY DBMSS WERE FOUND ONLY IN LARGE ORGANIZATIONS WITH THE COMPUTER HARDWARE NEEDED TOSUPPORT LARGE DATA SETS.1960S NAVIGATIONAL DBMSAS COMPUTERS GREW IN CAPABILITY, THIS TRADE-OFF BECAME INCREASINGLY UNNECESSARY AND A NUMBER OFGENERAL-PURPOSE DATABASE SYSTEMS EMERGED; BY THE MID-1960S THERE WERE A NUMBER OF SUCH SYSTEMSIN COMMERCIAL USE. INTEREST IN A STANDARD BEGAN TO GROW, AND CHARLES BACHMAN, AUTHOR OF ONE SUCHPRODUCT, INTEGRATED DATA STORE (IDS), FOUNDED THE "DATABASE TASK GROUP" WITHIN CODASYL, THE GROUPRESPONSIBLE FOR THE CREATION AND STANDARDIZATION OF COBOL. IN 1971 THEY DELIVERED THEIR STANDARD,WHICH GENERALLY BECAME KNOWN AS THE "CODASYL APPROACH", AND SOON THERE WERE A NUMBER OFCOMMERCIAL PRODUCTS BASED ON IT AVAILABLE.THE CODASYL APPROACH WAS BASED ON THE "MANUAL" NAVIGATION OF A LINKED DATA SET WHICH WAS FORMEDINTO A LARGE NETWORK. SIMPLE QUERIES LIKE "FIND ALL THE PEOPLE IN INDIA" REQUIRED THE PROGRAM TO WALKTHE ENTIRE DATA SET AND COLLECT THE MATCHING RESULTS. THERE WAS, ESSENTIALLY, NO CONCEPT OF "FIND"OR "SEARCH". THIS MIGHT SOUND LIKE A SERIOUS LIMITATION TODAY, BUT IN AN ERA WHEN THE DATA WAS MOSTOFTEN STORED ON MAGNETIC TAPE SUCH OPERATIONS WERE TOO EXPENSIVE TO CONTEMPLATE ANYWAY.IBM ALSO HAD THEIR OWN DBMS SYSTEM IN 1968, KNOWN AS IMS. IMS WAS A DEVELOPMENT OF SOFTWAREWRITTEN FOR THE APOLLO PROGRAM ON THE SYSTEM/360. IMS WAS GENERALLY SIMILAR IN CONCEPT TO CODASYL,BUT USED A STRICT HIERARCHY FOR ITS MODEL OF DATA NAVIGATION INSTEAD OF CODASYLS NETWORK MODEL.BOTH CONCEPTS LATER BECAME KNOWN AS NAVIGATIONAL DATABASES DUE TO THE WAY DATA WAS ACCESSED,AND BACHMANS 1973 TURING AWARD AWARD PRESENTATION WAS THE PROGRAMMER AS NAVIGATOR. IMS ISCLASSIFIED AS A HIERARCHICAL DATABASE. IDS AND IDMS, BOTH CODASYL DATABASES, AS WELL AS CINCOMSTOTAL DATABASE ARE CLASSIFIED AS NETWORK DATABASES.1970S RELATIONAL DBMSEDGAR CODD WORKED AT IBM IN SAN JOSE, CALIFORNIA, IN ONE OF THEIR OFFSHOOT OFFICES THAT WASPRIMARILY INVOLVED IN THE DEVELOPMENT OF HARD DISK SYSTEMS. HE WAS UNHAPPY WITH THE NAVIGATIONALMODEL OF THE CODASYL APPROACH, NOTABLY THE LACK OF A "SEARCH" FACILITY WHICH WAS BECOMINGINCREASINGLY USEFUL. IN 1970, HE WROTE A NUMBER OF PAPERS THAT OUTLINED A NEW APPROACH TO DATABASECONSTRUCTION THAT EVENTUALLY CULMINATED IN THE GROUNDBREAKING A RELATIONAL MODEL OF DATA FORLARGE SHARED DATA BANKS.
  3. 3. IN THIS PAPER, HE DESCRIBED A NEW SYSTEM FOR STORING AND WORKING WITH LARGE DATABASES. INSTEAD OFRECORDS BEING STORED IN SOME SORT OF LINKED LIST OF FREE-FORM RECORDS AS IN CODASYL, CODDS IDEAWAS TO USE A "TABLE" OF FIXED-LENGTH RECORDS. A LINKED-LIST SYSTEM WOULD BE VERY INEFFICIENT WHENSTORING "SPARSE" DATABASES WHERE SOME OF THE DATA FOR ANY ONE RECORD COULD BE LEFT EMPTY. THERELATIONAL MODEL SOLVED THIS BY SPLITTING THE DATA INTO A SERIES OF NORMALIZED TABLES, WITH OPTIONALELEMENTS BEING MOVED OUT OF THE MAIN TABLE TO WHERE THEY WOULD TAKE UP ROOM ONLY IF NEEDED.IN THE RELATIONAL MODEL, RELATED RECORDS ARE LINKED TOGETHER WITH A "KEY".END 1970S SQL DBMSIBM STARTED WORKING ON A PROTOTYPE SYSTEM LOOSELY BASED ON CODDS CONCEPTS AS SYSTEM R IN THEEARLY 1970S. THE FIRST "QUICKIE" VERSION WAS READY IN 1974/5, AND WORK THEN STARTED ON MULTI-TABLESYSTEMS IN WHICH THE DATA COULD BE BROKEN DOW N SO THAT ALL OF THE DATA FOR A RECORD (MUCH OFWHICH IS OFTEN OPTIONAL) DID NOT HAVE TO BE STORED IN A SINGLE LARGE "CHUNK". SUBSEQUENT MULTI-USERVERSIONS WERE TESTED BY CUSTOMERS IN 1978 AND 1979, BY W HICH TIME A STANDARDIZED QUERY LANGUAGE,SQL, HAD BEEN ADDED. CODDS IDEAS WERE ESTABLISHING THEMSELVES AS BOTH WORKABLE AND SUPERIOR TOCODASYL, PUSHING IBM TO DEVELOP A TRUE PRODUCTION VERSION OF SYSTEM R, KNOWN AS SQL/DS, AND, LATER,DATABASE 2 (DB2).MANY OF THE PEOPLE INVOLVED WITH INGRES BECAME CONVINCED OF THE FUTURE COMMERCIAL SUCCESS OFSUCH SYSTEMS, AND FORMED THEIR OWN COMPANIES TO COMMERCIALIZE THE WORK BUT WITH AN SQLINTERFACE. SYBASE, INFORMIX, NONSTOP SQL AND EVENTUALLY INGRES ITSELF WERE ALL BEING SOLD ASOFFSHOOTS TO THE ORIGINAL INGRES PRODUCT IN THE 1980S. EVEN MICROSOFT SQL SERVER IS ACTUALLY A RE-BUILT VERSION OF SYBASE, AND THUS, INGRES. ONLY LARRY ELLISONS ORACLE STARTED FROM A DIFFERENTCHAIN, BASED ON IBMS PAPERS ON SYSTEM R, AND BEAT IBM TO MARKET WHEN THE FIRST VERSION WAS
  4. 4. RELEASED IN 1978.STONEBRAKER WENT ON TO APPLY THE LESSONS FROM INGRES TO DEVELOP A NEW DATABASE, POSTGRES, W HICHIS NOW KNOW N AS POSTGRESQL. POSTGRESQL IS PRIMARILY USED FOR GLOBAL MISSION CRITICAL APPLICATIONS(THE .ORG AND .INFO DOMAIN NAME REGISTRIES USE IT AS THEIR PRIMARY DATA STORE, AS DO MANY LARGECOMPANIES AND FINANCIAL INSTITUTIONS).IN SWEDEN, CODDS PAPER WAS ALSO READ AND MIMER SQL WAS DEVELOPED FROM THE MID-70S AT UPPSALAUNIVERSITY. IN 1984, THIS PROJECT WAS CONSOLIDATED INTO AN INDEPENDENT ENTERPRISE. IN THE EARLY 1980S,MIMER INTRODUCED TRANSACTION HANDLING FOR HIGH ROBUSTNESS IN APPLICATIONS, AN IDEA THAT WASSUBSEQUENTLY IMPLEMENTED ON MOST OTHER DBMS.DEFINITION OF DATABASE:A DATABASE IS A COLLECTION OF OCCURRENCE OF MULTIPLE RECORD TYPES CONTAINING THE RELATIONSHIPBETWEEN RECORDS, DATA AGGREGATE AND DATA ITEMS. A DATABASE MAY BE DEFINED ASA DATABASE IS A COLLECTION OF INTERRELATED DATA STORE TOGETHER WITHOUT HARMFUL AND UNNECESSARYREDUNDANCY (DUPLICATE DATA) TO SERVE MULTIPLE APPLICATIONS THE DATA IS STORED SO THAT THEY ARE INDEPENDENT OF PROGRAMS, WHICH USE THE DATA. A COMMON ANDCONTROL APPROACH IS USED IN ADDING THE NEW DATA, MODIFYING AND RETRIEVING EXISTING DATA OR DELETIONOF DATA WITHIN THE DATABASE. A DATABASE MAY BE DESIGN FOR BATCH PROCESSING, REAL TIME PROCESSINGOR ON LINE PROCESSING.DATABASE SYSTEM DATABASE SYSTEM IS AN INTEGRATED COLLECTION OF RELATED FILES ALONG WITH THE DETAIL ABOUT THEIRDEFINITION, INTERPRETATION, MANIPULATION AND MAINTENANCE. IT IS A SYSTEM, WHICH SATISFIED THE DATANEED FOR VARIOUS APPLICATIONS IN AN ORGANIZATION WITHOUT UNNECESSARY REDUNDANCY. A DATABASESYSTEM IS BASED ON THE DATA. ALSO A DATABASE SYSTEM CAN BE RUN OR EXECUTED BY USING SOFTWARECALLED DBMS (DATABASE MANAGEMENT SYSTEM). A DATABASE SYSTEM CONTROLS THE DATA FROMUNAUTHORIZED ACCESS.FOUNDATION DATA CONCEPT
  5. 5. A HIERARCHY OF SEVERAL LEVELS OF DATA HAS BEEN DEVISED THAT DIFFERENTIATES BETWEEN DIFFERENTGROUPINGS, OR ELEMENTS, OF DATA. DATA ARE LOGICALLY ORGANIZED INTO: CHARACTER IT IS THE MOST BASIC LOGICAL DATA ELEMENT. IT CONSISTS OF A SINGLE ALPHABETIC, NUMERIC, OR OTHERSYMBOL. FIELD IT CONSISTS OF A GROUPING OF CHARACTERS. A DATA FIELD REPRESENTS AN ATTRIBUTE (A CHARACTERISTICOR QUALITY) OF SOME ENTITY (OBJECT, PERSON, PLACE, OR EVENT). RECORD THE RELATED FIELDS OF DATA ARE GROUPED TO FORM A RECORD. THUS, A RECORD REPRESENTS ACOLLECTION OF ATTRIBUTES THAT DESCRIBE AN ENTITY. FIXED-LENGTH RECORDS CONTAIN, A FIXED NUMBER OFFIXED-LENGTH DATA FIELDS. VARIABLE-LENGTH RECORDS CONTAIN A VARIABLE NUMBER OF FIELDS AND FIELDLENGTHS. FILE A GROUP OF RELATED RECORDS IS KNOWN AS A DATA FILE, OR TABLE. FILES ARE FREQUENTLY CLASSIFIED BYTHE APPLICATION FOR WHICH THEY AR PRIMARILY USED, SUCH AS A PAYROLL FILE OR AN INVENTORY FILE, OR THETYPE OF DATA THEY CONTAIN, SUCH AS A DOCUMENT FILE OR A GRAPHICAL IMAGE FILE. FILES ARE ALSOCLASSIFIED BY THEIR PERMANENCE, FOR EXAMPLE, A MASTER FILE VERSUS A TRANSACTION FILE. A TRANSACTIONFILE WOULD CONTAIN RECORDS OFALL TRANSACTIONS OCCURRING DURING A PERIOD, WHEREAS A MASTER FILE CONTAINS ALL THE PERMANENTRECORDS. A HISTORY FILE IS AN OBSOLETE TRANSACTION OR MASTER FILE RETAINED FOR BACKUP PURPOSES ORFOR LONG-TERM HISTORICAL STORAGE CALLED ARCHIVAL STORAGE.VARIOUS CHARACTERISTICS OF DBMS:THE MAJOR CHARACTERISTICS OF DATABASE APPROACH ARE: • SELF-DESCRIBING NATURE OF A DATABASE SYSTEM • INSULATION BETWEEN PROGRAMS AND DATA, AND DATA ABSTRACTION • SUPPORT OF MULTIPLE VIEWS OF THE DATA
  6. 6. • SHARING OF DATA AND MULTI USER TRANSACTION PROCESSINGDEFINITION OF DBMS:A DATABASE MANAGEMENT SYSTEM (DBMS) IS THE COMBINATION OF DATA, HARDWARE, SOFTWARE AND USERS TOHELP AN ENTERPRISE MANAGE ITS OPERATIONAL DATA. THE MAIN FUNCTION OF A DBMS IS TO PROVIDE EFFICIENT AND RELIABLE METHODS OF DATA RETRIEVAL TOMANY USERS. EFFICIENT DATA RETRIEVAL IS AN ESSENTIAL FUNCTION OF DATABASE SYSTEMS. DBMS MUST BEABLE TO DEAL WITH SEVERAL USERS WHO TRY TO SIMULTANEOUSLY ACCESS SEVERAL ITEMS AND MOSTFREQUENTLY, THE SAME DATA ITEM A DBMS IS A SET OF PROGRAMS THAT IS USED TO STORE AND MANIPULATIONDATA THAT INCLUDE THE FOLLOWING: • ADDING NEW DATA, FOR EXAMPLE ADDING DETAILS OF NEW STUDENT. • DELETING UNWANTED DATA, FOR EXAMPLE DELETING THE DETAILS OF STUDENTS W HO HAVE COMPLETEDCOURSE. • CHANGING EXISTING DATA, FOR EXAMPLE MODIFYING THE FEE PAID BY THE STUDENT.VARIOUS COMPONENTS OF DBMS:BASIC COMPONENTS: A DATABASE SYSTEM HAS FOUR COMPONENTS. THESE FOUR COMPONENTS ARE IMPORTANTFOR UNDERSTANDING AND DESIGNING THE DATABASE SYSTEM. THESE ARE: 1. DATA 2. HARDWARE 3. SOFTWARE 4. USERS1. DATA AS WE HAVE DISCUSSED ABOVE, DATA IS RAW HAND INFORMATION COLLECTED BY US. DATA IS MADE UP OFDATA ITEM OR DATA AGGREGATE. A DATA ITEM IS THE SMALLEST UNIT OF NAMED DATA: IT MAY CONSIST OF BITS ORBYTES. A DATA ITEM IS OFTEN REFERRED TO AS FIELD OR DATA ELEMENT. A DATA AGGREGATE IS THE COLLECTIONOF DATA ITEMS WITHIN THE RECORD, WHICH IS GIVEN A NAME AND REFERRED AS A WHOLE. DATA CAN BECOLLECTED ORALLY OR WRITTEN. A DATABASE CAN BE INTEGRATED AND SHARED. DATA STORED IN A SYSTEM ISPARTITION INTO ONE OR TWO DATABASES. SO IF BY CHANCE DATA LOST OR DAMAGED AT ONE PLACE, THEN IT CANBE ACCESSED FROM THE SECOND PLACE BY USING THE SHARING FACILITY OF DATA BASE SYSTEM. SO A SHAREDDATA ALSO CANE BE REUSED ACCORDING TO THE USER‟S REQUIREMENT. ALSO DATA MUST BE IN THE INTEGRATEDFORM. INTEGRATION MEANS DATA SHOULD BE IN UNIQUE FORM I.E. DATA COLLECTED BY USING A WELL-DEFINED
  7. 7. MANNER WITH NO REDUNDANCY, FOR EXAMPLE ROLL NUMBER IN A CLASS IS NON-REDUNDANT FORM AND SOTHESE HAVE UNIQUE RESISTANCE, BUT NAMES IN CLASS MAY BE IN THE REDUNDANT FORM AND CAN CREATE LOTOF PROBLEMS LATER ON IN USING AND ACCESSING THE DATA.2. HARDWARE HARDWARE IS ALSO A MAJOR AND PRIMARY PART OF THE DATABASE. WITHOUT HARDWARE NOTHING CAN BEDONE. THE DEFINITION OF HARDWARE IS “W HICH WE CAN TOUCH AND SEE”, I.E. IT HAS PHYSICAL EXISTENCES. ALLPHYSICAL QUANTITY OR ITEMS ARE IN THIS CATEGORY. FOR EXAMPLE, ALL THE HARDWARE INPUT/OUTPUT ANDSTORAGE DEVICES LIKE KEYBOARD, MOUSE, SCANNER, MONITOR, STORAGE DEVICES (HARD DISK, FLOPPY DISK,MAGNETIC DISK, AND MAGNETIC DRUM) ETC. ARE COMMONLY USED WITH A COMPUTER SYSTEM.3. SOFTWARE SOFTWARE IS ANOTHER MAJOR PART OF THE DATABASE SYSTEM. IT IS THE OTHER SIDE OF HARDWARE.HARDWARE AND SOFTWARE ARE TWO SIDES OF A COIN. THEY GO SIDE BY SIDE. SOFTWARE IS A SYSTEM.SOFTWARE ARE FURTHER SUBDIVIDED INTO TWO CATEGORIES, FIRST TYPE IS SYSTEM SOFTWARE (LIKE ALL THEOPERATING SYSTEMS, ALL THE LANGUAGES AND SYSTEM PACKAGES ETC.) AND SECOND ONE IS AN APPLICATIONSOFTWARE (PAYROLL, ELECTRICITY BILLING, HOSPITAL MANAGEMENT AND HOSTEL ADMINISTRATION ETC.). WE CANDEFINE SOFTWARE AS WHICH WE CANNOT TOUCH AND SEE. SOFTWARE ONLY CAN EXECUTE. BY USING SOFTWARE,DATA CAN BE MANIPULATED, ORGANIZED AND STORED. -4. USERS WITHOUT USER ALL OF THE ABOVE SAID COMPONENTS (DATA, HARDWARE & SOFTWARE) ARE MEANING LESS.USER CAN COLLECT THE DATA, OPERATE AND HANDLE THE HARDWARE. ALSO OPERATOR FEEDS THE DATA ANDARRANGES THE DATA IN ORDER BY EXECUTING THE SOFTWARE. OTHER COMPONENTS 1. PEOPLE - DATABASE ADMINISTRATOR; SYSTEM DEVELOPER; END USER. 2. CASE TOOLS: COMPUTER-AIDED SOFTWARE ENGINEERING (CASE) TOOLS. 3. USER INTERFACE - MICROSOFT ACCESS; POWERBUILDER. 4. APPLICATION PROGRAMS - POWERBUILDER SCRIPT LANGUAGE; VISUAL BASIC; C++; COBOL. 5. REPOSITORY - STORE DEFINITIONS OF DATA CALLED METADATA, SCREEN AND REPORT FORMATS, MENUDEFINITIONS, ETC. 6. DATABASE - STORE ACTUAL OCCURRENCES DATA.VARIOUS FUNCTIONS OF DBMS:THESE FUNCTIONS WILL INCLUDE SUPPORT FOR AT LEAST ALL OF THE FOLLOWING:
  8. 8. • DATA DEFINITION: THE DBMS MUST BE ABLE TO ACCEPT DATA DEFINITIONS (EXTERNAL SCHEMAS, THECONCEPTUAL SCHEMA, THE INTERNAL SCHEMA, AND ALL ASSOCIATED MAPPINGS) IN SOURCE FORM AND CONVERTTHEM TO THE APPROPRIATE OBJECT FORM. • DATA MANIPU1ATION: THE DBMS MUST BE ABLE TO HANDLE REQUESTS FROM THE USERS TO RETRIEVE,UPDATE, OR DELETE EXISTING DATA THE DATABASE, OR TO ADD NEW DATA TO THE DATABASE. IN OTHER WORDS,THE DBMS MUST INCLUDE A DATA MANIPULATION LANGUAGE (DML) PROCESSOR COMPONENT. • DATA SECURITY AND INTEGRITY: THE DBMS MUST MONITOR USER REQUESTS AND REJECT ANY ATTEMPT TOVIOLATE THE SECURITY AND INTEGRITY RULES DEFINED BY THE DBA. • DATA RECOVERY AND CONCURRENCY: THE DBMS - OR ELSE SOME OTHER RELATED SOFTWARE COMPONENT,USUALLY CALLED THE TRANSACTION MANAGER - MUST ENFORCE CERTAIN RECOVERY AND CONCURRENCYCONTROLS. • DATA DICTIONARY: THE DBMS MUST PROVIDE A DATA DICTIONARY FUNCTION. THE DATA DICTIONARY CAN BEREGARDED AS A DATABASE IN ITS OWN RIGHT (BUT A SYSTEM DATABASE, RATHER THAN A USER DATABASE). THEDICTIONARY CONTAINS “DATA ABOUT THE DATA” (SOMETIMES CALLED METADATA) - THAT IS, DEFINITIONS OF OTHEROBJECTS IN THE SYSTEM - RATHER THAN JUST”RAW DATA.” PERFORMANCE: IT GOES WITHOUT SAYING THAT THE DBMS SHOULD PERFORM ALL OF THE FUNCTIONS IDENTIFIED ABOVE AS EFFICIENTLY AS POSSIBLE.ADVANTAGES AND DISADVANTAGES OF DBMS:ADVANTAGES OF DBMS: ONE OF THE MAJOR ADVANTAGES OF USING A DATABASE SYSTEM IS THAT THE ORGANIZATION CAN BE HANDLEDEASILY AND HAVE CENTRALIZED MANAGEMENT AND CONTROL OVER THE DATA BY THE DBA. SOME MORE AND MAINADVANTAGES OF DATABASE MANAGEMENT SYSTEM ARE GIVEN BELOW:THE MAIN ADVANTAGES OF DBMS ARE:1. CONTROLLING REDUNDANCY IN A DBMS THERE IS NO REDUNDANCY (DUPLICATE DATA). IF ANY TYPE OF DUPLICATE DATA ARISES, THEN DBACAN CONTROL AND ARRANGE DATA IN NON-REDUNDANT WAY. IT STORES THE DATA ON THE BASIS OF A PRIMARYKEY, W HICH IS ALWAYS UNIQUE KEY AND HAVE NON-REDUNDANT INFORMATION. FOR EXAMPLE, ROLL NO IS THEPRIMARY KEY TO STORE THE STUDENT DATA.
  9. 9. IN TRADITIONAL FILE PROCESSING, EVERY USER GROUP MAINTAINS ITS OWN FILES. EACH GROUP INDEPENDENTLYKEEPS FILES ON THEIR DB E.G., STUDENTS. THEREFORE, MUCH OF THE DATA IS STORED TWICE OR MORE.REDUNDANCY LEADS TO SEVERAL PROBLEMS: • DUPLICATION OF EFFORT • STORAGE SPACE WASTED WHEN THE SAME DATA IS STORED REPEATEDLY FILES THAT REPRESENT THE SAME DATA MAY BECOME INCONSISTENT (SINCE THE UPDATES ARE APPLIEDINDEPENDENTLY BY EACH USERS GROUP).WE CAN USE CONTROLLED REDUNDANCY.2. RESTRICTING UNAUTHORIZED ACCESS A DBMS SHOULD PROVIDE A SECURITY AND AUTHORIZATION SUBSYSTEM. • SOME DB USERS WILL NOT BE AUTHORIZED TO ACCESS ALL INFORMATION IN THE DB (E.G., FINANCIAL DATA). • SOME USERS ARE ALLOWED ONLY TO RETRIEVE DATA. • SOME USERS ARE ALLOWED BOTH TO RETRIEVE AND TO UPDATE DATABASE.3. PROVIDING PERSISTENT STORAGE FOR PROGRAM OBJECTS AND DATA STRUCTURES DATA STRUCTURE PROVIDED BY DBMS MUST BE COMPATIBLE WITH THE PROGRAMMING LANGUAGE‟S DATASTRUCTURES. E.G., OBJECT ORIENTED DBMS ARE COMPATIBLE WITH PROGRAMMING LANGUAGES SUCH AS C++,SMALL TALK, AND THE DBMS SOFTWARE AUTOMATICALLY PERFORMS CONVERSIONS BETWEEN PROGRAMMINGDATA STRUCTURE AND FILE FORMATS.4. PERMITTING INFERENCING AND ACTIONS USING DEDUCTION RULES DEDUCTIVE DATABASE SYSTEMS PROVIDE CAPABILITIES FOR DEFINING DEDUCTION RULES FOR INFERENCINGNEW INFORMATION FROM THE STORED DATABASE FACTS.5. INCONSISTENCY CAN BE REDUCED IN A DATABASE SYSTEM TO SOME EXTENT DATA IS STORED IN, INCONSISTENT WAY. INCONSISTENCY IS ANOTHERFORM OF DELICACY. SUPPOSE THAT AN EM1OYEE “JAPNEET” WORK IN DEPARTMENT “COMPUTER” IS REPRESENTEDBY TWO DISTINCT ENTRIES IN A DATABASE. SO WAY INCONSISTENT DATA IS STORED AND DBA CAN REMOVE THISINCONSISTENT DATA BY USING DBMS.6. DATA CAN BE SHARED IN A DATABASE SYSTEM DATA CAN BE EASILY SHARED BY DIFFERENT USERS. FOR EXAMPLE, STUDENT DATA CANBE SHARE BY TEACHER DEPARTMENT, ADMINISTRATIVE BLOCK, ACCOUNTS BRANCH ARID LABORATORY ETC.7. STANDARD CAN BE ENFORCED OR MAINTAINED
  10. 10. BY USING DATABASE SYSTEM, STANDARD CAN BE MAINTAINED IN AN ORGANIZATION. DBA IS OVERALLCONTROLLER OF DATABASE SYSTEM. DATABASE IS MANUALLY COMPUTED, BUT W HEN DBA USES A DBMS ANDENTER THE DATA IN COMPUTER, THEN STANDARD CAN BE ENFORCED OR MAINTAINED BY USING THECOMPUTERIZED SYSTEM.8. SECURITY CAN BE MAINTAINED PASSWORDS CAN BE APPLIED IN A DATABASE SYSTEM OR FILE CAN BE SECURED BY DBA. ALSO IN A DATABASESYSTEM, THERE ARE DIFFERENT CODING TECHNIQUES TO CODE THE DATA I.E. SAFE THE DATA FROMUNAUTHORIZED ACCESS. ALSO IT PROVIDES LOGIN FACILITY TO USE FOR SECURING AND SAVING THE DATA EITHERBY ACCIDENTAL THREAT OR BY INTENTIONAL THREAT. SAME RECOVERY PROCEDURE CAN BE ALSO MAINTAINED TOACCESS THE DATA BY USING THE DBMS FACILITY.9. INTEGRITY CAN BE MAINTAINED IN A DATABASE SYSTEM, DATA CAN BE WRITTEN OR STORED IN INTEGRATED WAY. INTEGRATION MEANSUNIFICATION AND SEQUENCING OF DATA. IN OTHER WORDS IT CAN BE DEFINED AS “THE DATA CONTAINED IN THEDATA BASE IS BOTH ACCURATE AND CONSISTENT”. „DATA CAN BE ACCESSED IF IT IS COMPILED IN A UNIQUE FORM.WE CAN TAKE PRIMARY KEY AD SOME SECONDARY KEY FOR INTEGRATION OF DATA. CENTRALIZED CONTROL CANALSO ENSURE THAT ADEQUATE CHECKS ARE INCORPORATED IN THE DBMS TO PROVIDE DATA INTEGRITY.10. CONFLICTION CAN BE REMOVED IN A DATABASE SYSTEM, DATA CAN BE WRITTEN OR ARRANGED IN A WELL-DEFINED MANNER BY DBA. SO THEREIS NO CONFLICTION BETWEEN THE DATABASES. DBA SELECT THE BEST FILE STRUCTURE AND ACCESSINGSTRATEGY TO GET BETTER PERFORMANCE FOR THE REPRESENTATION AND USE OF THE DATA.11. PROVIDING MULTIPLE USER INTERFACES FOR EXAMPLE QUERY LANGUAGES, PROGRAMMING LANGUAGES INTERFACES, FORMS, MENU- DRIVENINTERFACES, ETC.12. REPRESENTING COMPLEX RELATIONSHIPS AMONG DATA IT IS USED TO REPRESENT COMPLEX RELATIONSHIPS AMONG DATA13. PROVIDING BACKUP AND RECOVERY THE DBMS ALSO PROVIDES BACK UP AND RECOVERY FEATURES.DISADVANTAGES OF DBMS:
  11. 11. DATABASE MANAGEMENT SYSTEM HAS MANY ADVANTAGES, BUT DUE TO SOME MAJOR PROBLEM ARISE IN USINGTHE DBMS, IT HAS SOME DISADVANTAGES. THESE ARE EXPLAINED AS:1.COST A SIGNIFICANT DISADVANTAGE OF DBMS IS COST. IN ADDITION TO THE COST OF PURCHASING OR DEVELOPINGTHE SOFTWARE, THE ORGANIZATION *111 ALSO PURCHASE OR UPGRADE THE HARDWARE AND SO IT BECOMES ACOSTLY SYSTEM. ALSO ADDITIONAL COST OCCURS DUE TO MIGRATION OF DATA FROM ONE ENVIRONMENT OF DBMSTO ANOTHER ENVIRONMENT.2. PROBLEMS ASSOCIATED WITH CENTRALIZATION CENTRALIZATION ALSO MEANS THAT DATA IS ACCESSIBLE FROM A SINGLE SOURCE. AS WE KNOW THECENTRALIZED DATA CAN BE ACCESSED BY EACH USER, SO THERE IS NO SECURITY OF DATA FROM UNAUTHORIZEDACCESS AND DATA CAN BE DAMAGED OR LOST.3. COMPLEXITY OF BACKUP AND RECOVERY BACKUP AND RECOVERY ARE FAIRLY COMPLEX IN DBMS ENVIRONMENT. AS IN A DBMS, IF YOU TAKE A BACKUPOF THE DATA THEN IT MAY AFFECT THE MULTI-USER DATABASE SYSTEM WHICH IS IN OPERATION. DAMAGEDATABASE CAN BE RECOVERED FROM THE BACKUP FLOPPY, BUT ITERATE DUPLICACY IN LOADING TO THECONCURRENT MULTI-USER DATABASE SYSTEM.4. CONFIDENTIALITY, PRIVACY AND SECURITY WHEN INFORMATION IS CENTRALIZED AND IS MADE AVAILABLE TO USERS FROM REMOTE LOCATIONS, THEPOSSIBILITIES OF ABUSE ARE OFTEN MORE THAN IN A CONVENTIONAL SYSTEM. TO REDUCE THE CHANCES OFUNAUTHORIZED USERS ACCESSING SENSITIVE INFORMATION, IT IS NECESSARY TO TAKE TECHNICAL,ADMINISTRATIVE AND, POSSIBLY, LEGAL MEASURES. MOST, DATABASES STORE VALUABLE INFORMATION THAT MUSTBE PROTECTED AGAINST DELIBERATE TRESPASS AND DESTRUCTION.5. DATA QUALITY SINCE THE DATABASE IS ACCESSIBLE TO USERS REMOTELY, ADEQUATE CONTROLS ARE NEEDED TO CONTROLUSERS UPDATING DATA AND TO CONTROL DATA QUALITY. WITH INCREASED NUMBER OF USERS ACCESSING DATADIRECTLY, THERE ARE ENORMOUS OPPORTUNITIES FOR USERS TO DAMAGE THE DATA. UNLESS THERE ARESUITABLE CONTROLS, THE DATA QUALITY MAY BE COMPROMISED.6. DATA INTEGRITY SINCE A LARGE NUMBER OF USERS COULD BE USING .A DATABASE CONCURRENTLY, TECHNICAL SAFEGUARDSARE NECESSARY TO ENSURE THAT THE DATA REMAIN CORRECT DURING OPERATION. THE MAIN THREAT TO DATAINTEGRITY COMES FROM SEVERAL DIFFERENT USERS ATTEMPTING TO UPDATE THE SAME DATA AT THE SAME TIME.THE DATABASE THEREFORE NEEDS TO BE PROTECTED AGAINST INADVERTENT CHANGES BY THE USERS.7. ENTERPRISE VULNERABILITY
  12. 12. CENTRALIZING ALL DATA OF AN ENTERPRISE IN ONE DATABASE MAY MEAN THAT THE DATABASE BECOMES ANINDISPENSABLE RESOURCE. THE SURVIVAL OF THE ENTERPRISE MAY DEPEND ON RELIABLE INFORMATION BEINGAVAILABLE FROM ITS DATABASE. THE ENTERPRISE THEREFORE BECOMES VULNERABLE TO THE DESTRUCTION OFTHE DATABASE OR TO UNAUTHORIZED MODIFICATION OF THE DATABASE.8. THE COST OF USING A DBMS CONVENTIONAL DATA PROCESSING SYSTEMS ARE TYPICALLY DESIGNED TO RUN A NUMBER OF WELL-DEFINED,PREPLANNED PROCESSES. SUCH SYSTEMS ARE OFTEN “TUNED” TO RUN EFFICIENTLY FOR THE PROCESSES THATTHEY WERE DESIGNED FOR. ALTHOUGH THE CONVENTIONAL SYSTEMS ARE USUALLY FAIRLY INFLEXIBLE IN THATNEW APPLICATIONS MAY BE DIFFICULT TO IMPLEMENT AND/OR EXPENSIVE TO RUN, THEY ARE USUALLY VERYEFFICIENT FOR THE APPLICATIONS THEY ARE DESIGNED FOR. THE DATABASE APPROACH ON THE OTHER HAND PROVIDES A FLEXIBLE ALTERNATIVE WHERE NEWAPPLICATIONS CAN BE DEVELOPED RELATIVELY INEXPENSIVELY. THE FLEXIBLE APPROACH IS NOT WITHOUT ITSCOSTS AND ONE OF THESE COSTS IS THE ADDITIONAL COST OF RUNNING APPLICATIONS THAT THE CONVENTIONALSYSTEM WAS DESIGNED FOR. USING STANDARDIZED SOFTWARE IS ALMOST ALWAYS LESS MACHINE EFFICIENTTHAN SPECIALIZED SOFTWARE.APPLICATION OF DBMS IN BUSINESS TODAY :ALL BUSINESSES/COMPANIES MAINTAIN AND USE DATA FOR DAY-TO-DAY BUSINESS OPERATIONS. A DATABASEMANAGEMENT SYSTEM IS THE SOFTWARE THAT IS USED TO STORE DATA, MAINTAIN THOSE DATA, AND PROVIDEEASY ACCESS TO STORED DATA. IT ALLOWS BUSINESS/COMPANY TO STORE DATA IN A CENTRAL LOCATION USING ASTANDARD FORMAT.DATA ARE A VALUABLE BUSINESS/COMPANY RESOURCE. GOOD DATA AND INFORMATION RETRIEVAL TECHNOLOGYCAN IMPROVE THE BUSINESS/COMPANYS ABILITY TO COMPETE IN AN INDUSTRY, DELIVER PRODUCTS TOCONSUMERS, AND EVALUATE OPPORTUNITIES. THE LOSS OR CONTAMINATION OF AN BUSINESS/COMPANYS DATACAN CONTRIBUTE TO FAILURE.A GOOD MANAGEMENT SYSTEM PROVIDES USERS WITH FACILITIES TO MAINTAIN STORED DATA, TOOLS TO CREATESCREENS USED TO VIEW AND UPDATE DATA, REPORT GENERATION CAPABILITIES, QUERY SERVICES TO OBTAINFAST ANSWERS TO QUESTIONS ABOUT THE DATA, AND COMMON INTERFACES TO SHARE DATA.WHAT ROLE DOES DATABASE MANAGEMENT PLAY IN MANAGING DATA AS A BUSINESS RESOURCE?THE ROLE IS ONE OF APPLYING INFORMATION SYSTEMS TECHNOLOGIES LIKE DATABASE MANAGEMENTDATA WAREHOUSING, AND OTHER DATA MANAGEMENT TOOLS TO THE TASK OF MANAGING AN ORGANIZATION‟SDATA RESOURCES TO MEET THE INFORMATION NEEDS OF THEIR BUSINESS STAKEHOLDERS.WHAT IS THE ROLE OF A DATABASE MANAGEMENT SYSTEM IN A BUSINESS INFORMATION SYSTEM?A DATABASE MANAGEMENT SYSTEM IS A SET OF COMPUTER PROGRAMS THAT CONTROLS THE CREATION,MAINTENANCE, AND USE OF THE DATABASES OF AN ORGANIZATION. MAJOR USES ARE DATABASE DEVELOPMENT,DATABASE INTERROGATION, DATABASE MAINTENANCE, AND DEVELOPMENT OF APPLICATION PROGRAMS.

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