Covers various advantages and disadvantages of data base management system in a comprehensive manner

1. ADVANTAGES AND
DISADVANAGES OF DBMS
PRESENTED BY:-
MOHIT SINGHAL
BCOM(HONS) SECTION – B
ROLL NO:- 2166

2. WHAT IS DBMS
"A DATABASE MANAGEMENT SYSTEM (DBMS) IS A COLLECTION OF
PROGRAMS THAT MANAGES THE DATABASE STRUCTURE AND CONTROLS
ACCESS TO THE DATA STORED IN THE DATABASE".
THE DBMS SERVES AS THE INTERMEDIARY BETWEEN THE USER AND THE
DATABASE. THE DATABASE STRUCTURE ITSELF IS STORED AS A COLLECTION
OF FILES, SO, WE CAN ACCESS THE DATA IN THOSE FILES THROUGH THE
DBMS.

3. ADVANTAGES OF DBMS

4. REDUCED DATA REDUNDANCY
DEFINITION - WHAT DOES DATA REDUNDANCY MEAN?
DATA REDUNDANCY IS A CONDITION CREATED WITHIN A DATABASE OR DATA STORAGE
TECHNOLOGY IN WHICH THE SAME PIECE OF DATA IS HELD IN TWO SEPARATE PLACES.
THIS CAN MEAN TWO DIFFERENT FIELDS WITHIN A SINGLE DATABASE, OR TWO DIFFERENT
SPOTS IN MULTIPLE SOFTWARE ENVIRONMENTS OR PLATFORMS. WHENEVER DATA IS
REPEATED, THIS BASICALLY CONSTITUTES DATA REDUNDANCY. THIS CAN OCCUR BY
ACCIDENT, BUT IS ALSO DONE DELIBERATELY FOR BACKUP AND RECOVERY PURPOSES.
DBMS ALLOWS USERS TO ACCESS CENTRALLY MANAGED DATABASE THAT REDUCES
REDUNDANCY AND SAVES STORAGE SPACE

5. ELIMINATION OF INCONSISTENCIES
DATA INCONSISTENCY IS A CONDITION THAT OCCURS BETWEEN FILES WHEN
SIMILAR DATA IS KEPT IN DIFFERENT FORMATS IN TWO DIFFERENT FILES, OR
WHEN MATCHING OF DATA MUST BE DONE BETWEEN FILES. AS A RESULT OF
THE DATA INCONSISTENCY, THESE FILES DUPLICATE SOME DATA SUCH AS
ADDRESSES AND NAMES, COMPROMISING DATA INTEGRITY.
BY A SYSTEM CALLED PROPAGATING UPDATES CHANGES MADE AT ONE PLACE
ARE AUTOMATICALLY MADE AT ALL SIMILAR LOCATIONS

6. DATA SECURITY
THE MORE USERS ACCESS THE DATA, THE GREATER THE RISKS OF
DATA SECURITY BREACHES. CORPORATIONS INVEST CONSIDERABLE
AMOUNTS OF TIME, EFFORT, AND MONEY TO ENSURE THAT
CORPORATE DATA ARE USED PROPERLY. A DBMS PROVIDES A
FRAMEWORK FOR BETTER ENFORCEMENT OF DATA PRIVACY AND
SECURITY POLICIES.
LEVEL 1 – WHETHER USER HAS AUTHORITY TO USE SYSTEM
LEVEL 2 – WHETHER DEMANDED FILE IS ACCESSIBLE
LEVEL 3 – ANALYSE PERMISSION TO ADD, MODIFY, OR DELETE THE
FILE

7. EASIER DATA ACCESS TO USERS
THE DBMS MAKES IT POSSIBLE TO PRODUCE QUICK ANSWERS TO AD HOC QUERIES. FROM A
DATABASE PERSPECTIVE, A QUERY IS A SPECIFIC REQUEST ISSUED TO THE DBMS FOR DATA
MANIPULATION—FOR EXAMPLE, TO READ OR UPDATE THE DATA. SIMPLY PUT, A QUERY IS A
QUESTION, AND AN AD HOC QUERY IS A SPUR-OF-THE-MOMENT QUESTION. THE DBMS
SENDS BACK AN ANSWER (CALLED THE QUERY RESULT SET) TO THE APPLICATION. FOR
EXAMPLE, END USERS, WHEN DEALING WITH LARGE AMOUNTS OF SALES DATA, MIGHT WANT
QUICK ANSWERS TO QUESTIONS (AD HOC QUERIES) SUCH AS:
- WHAT WAS THE VOLUME OF SALES BY PRODUCT DURING THE PAST SIX MONTHS?
- WHAT IS THE SALES BONUS FIGURE FOR EACH OF OUR SALESPEOPLE DURING THE PAST
THREE MONTHS?
- HOW MANY OF OUR CUSTOMERS HAVE CREDIT BALANCES OF 3,000 OR MORE?

8. IMPROVED DECISION MAKING
BETTER-MANAGED DATA AND IMPROVED DATA ACCESS MAKE IT
POSSIBLE TO GENERATE BETTER-QUALITY INFORMATION, ON
WHICH BETTER DECISIONS ARE BASED. THE QUALITY OF THE
INFORMATION GENERATED DEPENDS ON THE QUALITY OF THE
UNDERLYING DATA. DATA QUALITY IS A COMPREHENSIVE
APPROACH TO PROMOTING THE ACCURACY, VALIDITY, AND
TIMELINESS OF THE DATA. WHILE THE DBMS DOES NOT
GUARANTEE DATA QUALITY, IT PROVIDES A FRAMEWORK TO
FACILITATE DATA QUALITY INITIATIVES.

9. BACKUP AND RECOVERY
A DBMS MUST PROVIDE FACILITIES FOR RECOVERING FROM
HARDWARE OR SOFTWARE FAILURES. THE BACKUP AND RECOVERY
SUBSYSTEM OF THE DBMS IS RESPONSIBLE FOR RECOVERY. FOR
EXAMPLE, IF THE COMPUTER SYSTEM FAILS IN THE MIDDLE OF A
COMPLEX UPDATE PROGRAM, THE RECOVERY SUBSYSTEM IS
RESPONSIBLE FOR MAKING SURE THAT THE DATABASE IS RESTORED
TO THE STATE IT WAS IN BEFORE THE PROGRAM STARTED
EXECUTING.
OTHER REASONS MAY BE:-
1. DISK CRASH
2. SOFTWARE ERRORS

10. DISADVANTAGES OF
DBMS

11. HIGH INITIAL COST
RESOURCES
manpower
Skilled people are
required who
expect more
salaries
HARDWARE
Servers and
nodes are to be
used which may
costs lakhs
SOFTWARE
Complicated
softwares like
oracle,visual basic
generally cost
upto 25 lakhs

12. COMPLEXITY
DBMS IS COMPLEX, DIFFICULT, TIME CONSUMING TO DESIGN, DEVELOP AND ADMINISTER
THE PROVISION OF THE FUNCTIONALITY THAT IS EXPECTED OF A GOOD DBMS MAKES THE
DBMS AN EXTREMELY COMPLEX PIECE OF SOFTWARE. DATABASE DESIGNERS, DEVELOPERS,
DATABASE ADMINISTRATORS AND END-USERS MUST UNDERSTAND THIS FUNCTIONALITY TO
TAKE FULL ADVANTAGE OF IT. FAILURE TO UNDERSTAND THE SYSTEM CAN LEAD TO BAD DESIGN
DECISIONS, WHICH CAN HAVE SERIOUS CONSEQUENCES FOR AN ORGANIZATION.

13. COST OF CONVERSION
IN SOME SITUATIONS, THE COST OF THE DBMS AND EXTRA HARDWARE MAY BE INSIGNIFICANT
COMPARED WITH THE COST OF CONVERTING EXISTING APPLICATIONS TO RUN ON THE NEW
DBMS AND HARDWARE. THIS COST ALSO INCLUDES THE COST OF TRAINING STAFF TO USE THESE
NEW SYSTEMS AND POSSIBLY THE EMPLOYMENT OF SPECIALIST STAFF TO HELP WITH
CONVERSION AND RUNNING OF THE SYSTEM. THIS COST IS ONE OF THE MAIN REASONS WHY
SOME ORGANIZATIONS FEEL TIED TO THEIR CURRENT SYSTEMS AND CANNOT SWITCH TO
MODERN DATABASE TECHNOLOGY.

14. SECURITY ISSUES
• AS COMPUTERISED ENVIRONMENT IS EASIER TO BREAK AND THERE EXISTS NO MORAL
CHECK (HACKING ONLINE CLASSES MAY BE AVAILABLE)
• NO PHYSICAL NAVAIGATION
PEOPLE DON’T HAVE TO MOVE PHYSICALLY AND IT CAN BE DONE SITTING AT HOME AND
HAVING AN INTERNET CONNECTION
SO AS DATA IS CENTRALLY MANAGED AND CAN BE ACCESSED BY USERS, IT HAS SOME SECURITY
ISSUES

15. SLOWER RESPONSE
IN DATABASE SYSTEM THE DATABASE IS CENTRALLY MANAGED AND ACCESSED BY DIFFERENT
USERS ONLINE AND OFFLINE.
IT REQUIRES A POWERFUL SERVER.
SOMETIMES WHEN MANY USERS ACCESS THE SAME DATABASE IT MAY RESULT IN SLOWER
RESPONSE
EXAMPLE:- ON THE DAY WHEN DU RESULTS ARE DECLARED, MANY AUTHORISED USERS ACCESS
TO SAME DATABASE WHICH MAY RESULT IN SLOWER RESPONSE

16. THANK YOU