Lecture 1 (Part 2)

Question 1

What is a Transaction?

Answer 1

A transaction is a sequential set of operations which either are performed in its entirety or are not performed at all.

Question 2

What are Two Hazardous Situations?

Answer 2

1. System Failures

2. Concurrency

Question 3

What are System Failures?

Answer 3

Which may terminate the system in the midst of transaction execution

Question 4

What is a Concurrency?

Answer 4

Which may cause a transaction to retrieve inconsistent data created by other
transactions.

Question 5

What are two Types of Distributed Systems?

Answer 5

1. Homogenous

2. Heterogenous

Question 6

What is a Homogenous system?

Answer 6

A distributed system with the same subsystems at each site. (e.g. the same DBMS at each site)

Question 7

What is a Heterogeneous system?

Answer 7

A distributed system with at least two different subsystems over the entire system (e.g. two different DBMS)

Question 8

What is a Distributed Database System?

Answer 8

A distributed database (DDB) is a collection of multiple, logically interrelated databases distributed over a computer network

Question 9

What is a Distributed Database Management System?

Answer 9

A distributed database management system (DDBMS) is the software that manages the DDS and provides an access mechanism that makes this distribution transparent to the users.

Question 10

Distributed database system (DDBS) =

Answer 10

DBS + Communication