ACID Properties and Concurrent Accessing

Question 1

A

Answer 1

Atomicity - Transactions are either done, or not done, never partially applied

Question 2

C

Answer 2

Consistency - Referential integrity and other constraints must be adhered to

Question 3

I

Answer 3

Isolation - Transactions performed simultaneously must have the same result as if they were performed sequentially

Question 4

D

Answer 4

Durability - Transactions that have been committed must be done fully and remain so.

Question 5

Concurrent Access

Answer 5

Is ensuring that more than one user can at least view data at the same time

Question 6

Record Locking

Answer 6

Making a file read-only to anybody else who opens the file while changes are being made

Question 7

Deadlock

Answer 7

When 2 separate transactions lock the file the other transaction needs, thus both are in a state of waiting

Question 8

Serialisation

Answer 8

Create a clone of the data item so the user can make changes, then upload a copy of the clone to the database/ This will ensure no updates or changes can be lost due to uploading a copy of the local versions

Question 9

Timestamp Ordering

Answer 9

A non-lock way of concurrent access, so multiple people can

access the data at one time. The main process is that the lower timestamps occur first.