Advantages and disadvantages of DBMS

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

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