Week 3 - ACID Properties

Question 1

What is a transaction?

Answer 1

It is basically user programs that either read or write data to the database system

Question 2

Can you have multiple transaction running at the same time?

Answer 2

Yes

Question 3

How to obtain Concurrency with transactions

Answer 3

Using interleaves to execute the transaction but leave the database in a consistent state

Question 4

Atomicity

Answer 4

All or nothing

Question 5

Consistency

Answer 5

no violations of integrity constraints

think foreign keys, primary keys..etc, data replication etc

Question 6

Isolation

Answer 6

concurrent changes invisible => serializable

Question 7

Durability

Answer 7

committed updates persist

Question 8

Which of the following describes the atomicity principle of database transactions?

1) A database can only serve one user at a time.
2) All of the components of a transaction run in their entirety, or none of them run at all.
3) A database can only process one query at a time.
4) A database can only process one transaction at a time.

Answer 8

2) All of the components of a transaction run in their entirety, or none of them run at all.

Question 9

Which of the following describes the isolation principle of database transactions?

1) All of the components of a database transaction run in their entirety, or none of them run at all.
2) A database management system can only process on query at a time.
3) A database management system can process multiple transactions simultaneously.
4) Each transaction runs as if there is no other transaction running

Answer 9

4) Each transaction runs as if there is no other transaction running

Question 10

What is a sequence of reads and writes from/to a database called?

1) Process
2) Program
3) Transaction
4) Information

Answer 10

3) Transaction

Question 11

How does a database achieve concurrency?

1) By processing transactions as they come in.
2) By interleaving transactions.
3) By processing transactions at the same time.
4) By putting transactions in a queue.

Answer 11

2) By interleaving transactions.

Question 12

What are the four principles of database transactions?

1) Atomicity, Concurrency, Isolation, Durability
2) Atomicity, Consistency, Isolation, Durability
3) Atomicity, Consistency, Integrity, Durability

Answer 12

2) Atomicity, Consistency, Isolation, Durability

Question 13

Which of the following describes the atomicity principle of database transactions?

1) All of the components of a transaction run in their entirety, or none of them run at all.
2) A database can only process one transaction at a time.
3) A database can only process one query at a time.
4) A database can only serve one user at a time.

Answer 13

1) All of the components of a transaction run in their entirety, or none of them run at all.