Chapter 1 Introduction to DBMS : Important Questions and Answers : PYQS

 Chapter 1 Introduction to DBMS 

1 mark

(c) Explain various types of users in DBMS.

a) Enlist users of DBMS.

(a) What is a logical file ?

Answer: Logical file:  A logical file represents what is stored in a file and what operations can be performed on it. It is a representation of one or more physical files. 

(i) State different types of users of DBMS.

e) What are the different functions performed by DBA?

a) What is a physical file?

b) Define Database Management System.

Answer: A DBMS (Database Management Systems) is a software system that is used to manage, store and manipulate data. 

Q. What is database?

Answer: It is a collection of related data stored together so that users can efficiently retrieve the information.

j) Who are Naive users?

(h) Who are Naive users ?

b) Write a short note on sorted or sequential file organization.

(a) Write a short note on data independence.

- Data independence is concept in database management where changes made to physical structure or logical structure of data do not affect the way users of applications interact with the data.

They are of two types :

1) Physical Data Independence: It allows changes in physical storage of data (like moving to a different storage device or changing storage mechanisms) without affecting the way data is accessed or manipulated by users and applications. 

2) Logical Data Independence: It allows changes in the logical structure of the data (such as modifying tables, adding or removing attributes) without impacting the user-level interactions.

(g) List any two advantages of DBMS.

- 

1. Data Integrity: DBMS enforces rules to keep data accurate and consistent.
2. Security: DBMS ensures authorized access and guards against unauthorized use.
3. Reduced Redundancy: DBMS minimizes duplication, saving storage space.
4. Quick Retrieval: DBMS retrieves data efficiently using indexes and queries.
5. Concurrency Control: DBMS handles multiple users simultaneously, preventing conflicts.

4 mark

(a) Explain Hash file organization technique in detail.

a) What is data abstraction? What are different levels of data abstraction?

- It is the hiding of certain details of how data is stored and maintained in a database management system,

There are three levels of data abstraction:

1) Physical Level (Internal Level) : 

- It is lowest level of data abstraction.

- It describes how raw data is actually stored in physical storage devices.

- This level is hidden from programmers and end users.

- It is used by system architect and storage engineers.

2) Logical Level (Conceptual Level) :

- This level is higher than physical level.

- It decribes what data is stored in the database and relationship between those data.

- Database designers and administrators work at this level creating tables, views, etc.

3) View Level (External Level) :

- It is the highest level of abstraction.

- It described the way a particular user of application program views the data from database.

-  End users interact with database at this level.

(b) Write a short note on Data Abstraction.

d) Write a short note on data abstraction.

c) Explain overall DBMS structure with neat diagram.

(a) What is DBMS ? What are the advantages and disadvantages

of DBMS ?

- A Database Management System (DBMS) is software that provides an organized and efficient way to create, manage, store, retrieve, and manipulate large amounts of structured data. It acts as an intermediary between users and the physical storage of data, offering tools for data definition, data manipulation, and data control.

Advantages of DBMS:

1. Data Centralization: All data is stored in a single system, making management and access more efficient.

2. Data Integrity: DBMS enforces rules to ensure data accuracy and consistency, reducing errors.

3. Data Security: DBMS provides authentication, authorization, and encryption for safeguarding data from unauthorized access.

4. Reduced Data Redundancy: Data duplication is minimized, saving storage space and maintaining data consistency.

5. Efficient Data Retrieval: Indexed searching and optimized queries speed up data retrieval operations.

Disadvantages of DBMS:

1. Complexity: Setting up and maintaining a DBMS can be intricate, demanding specialized expertise.

2. Cost: Implementation, licensing, and maintenance expenses can be substantial over time.

3. Learning Curve: Users need time to learn how to interact with the DBMS interface effectively.

4. Performance Overhead: Managing data can introduce overhead that affects system performance.

5. Vendor Lock-In: Selecting a specific DBMS can lead to dependence on a particular vendor's technology.

(e) Write a note on functional components of DBMS.

Extra 

Q. What is file.

Answer: A file is a collection of related information.

Q. What are different types of files?

Answer: There are two types of files:

1) Logical file:  A logical file represents what is stored in a file and what operations can be performed on it. It is a representation of one or more physical files. 

2) Physical File : A physical file shows how the data is stored on a storage device and how  processing operations are made possible.  It is a collection of bytes stored on a storage device,

Q. What is file organization ?

Answer: It is a method of arranging records in a file on a secondary storage device.

It refers to the manner in which records of file may be accessed or modified.

Q. What are ways of file organization?

- There are 3 ways of file organization:

1) Heap File Organization:

2) Sorted File Organization :

3) Indexed File Organization

4) Hash File Organization

Q. What are disadvantages of file system?

Answer: 1) Seperated data: Data is scattered in various files, making it hard to find and manage information efficiently.

2) Isolated data: Files are independent, leading to duplication and makes it difficult to retrieve data.

3) Data redundancy: Same data is repeated in multiple files, wasting space and if a specific data present in multiple files has to be changed, all files have to be edited.

4) Concurrent Access Anomalies: Once a file is opened by a user, it cannot be used by another user, till first user closes the file.

5) Security Problem: It is difficult to control access to specific parts of data.

Q. File system vs dbms.
Answer:

Aspect	File System	DBMS
1. Cost	Economical	Requires higher investment
2. User System	Single-user	Multi-user
3. Data Access	Data retrieval and management is complex	Efficient data access and management
4. Data Integration	Data is isolated and scattered	Integrated, organized data
5. Security	Prone to security vulnerabilities	Offers robust security measures
6. Examples	C++, COBOL, VB	MS Access, Oracle, PostgreSQL
7. Data Sharing	Limited sharing capabilities	Efficient data sharing features
8. Complexity	Simpler structure and operations	Complex, feature-rich operations
9. Scalability	Less suitable for handling large amounts of data	Scales well for growing data needs
10. Concurrency	Lacks effective management of concurrent access	Handles concurrent access smoothly

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