Transactions and DBMS Architecture

Question 1

What is a DBMS?

Answer 1

Software system for defining, building, manipulating, and sharing databases efficiently

Question 2

What are the main goals of a DBMS

Answer 2

1. Data abstraction
2. Independence
3. Fault tolerance
4. Access control
5. Concurrency

Question 3

4 types of DBMS languages

Answer 3

1. Data Definition Language (DDL)
2. Data Manipulation Language (DML)
3. Data Control Language (DCL - access control)
4. Transaction Control Language (TCL)

Question 4

ACID

Answer 4

Atomicity
Consistency
Isolation
Durability

Question 5

Why is isolation important in transactions?

Answer 5

To maintain transactions do not interfere with each other, maintaining data integrity

Question 6

What is a dirty read in concurrency?

Answer 6

When a transaction reads data that has not been committed yet

Question 7

How does a DBMS prevent loss updates?

Answer 7

By using locks and ensuring proper transaction isolation

Question 8

What does the Query Optimizer do?

Answer 8

Determines the most efficient way to execute a query

Question 10

Recovery Manager

Answer 10

Restrores database to a consistent state after failures

Question 11

NoSQL

Answer 11

Databases that handle unstructured data, web-scale applications and horizontal scalability

Question 13

Main advantage of in-memory databases (IMDB)

Answer 13

Faster access since data is stored in RAM.

Question 14

Difference between two-tier and three-tier DBMS architectures

Answer 14

3-tier separates presentation, logic, and database services to improve scalability and modularity

Question 15

Cloud Database

Answer 15

Database hosted in managed in the cloud (DBaaS).