Views/Security/Transactions

Question 1

Advantages Views

Answer 1

Data independence
Security
Easier querying
Convenience/Customization

Question 2

Disadvantages of views

Answer 2

Updatable views are not always supported and are restrictive
Performance - Views add increased overhead: During query parsing and especially if they are materialized

Question 3

SQL privileges

Answer 3

SELECT - The user can retrieve data from table
INSERT - The user cam insert data into the table
UPDATE - The user can modify data in the table
DELETE - The user can delete rows from table
REFERENCES - The ability to reference columns of a named table in integrity constraints
USAGE - The ability to use domains, character sets and translations

INSERT and UPDATE can be restricted to certain columns

When a user creates a table they become the owner and have full privileges on the table

Question 4

GRANT

Answer 4

GRANT command gives privileges on database objects to users

Question 5

REVOKE

Answer 5

Command used to remove privileges on database objects from users

Question 6

Atomicity

Answer 6

Either all operations of the transaction are properly reflected in the database or none are

Question 7

Consistency

Answer 7

Execution of a transaction in isolation preserves the consistency of the database

Question 8

Isolation

Answer 8

Although multiple transactions may execute concurrently, each transaction must be unaware of other concurrently executing transaction

Question 9

Durability

Answer 9

After a transaction successfully completes, the change it has made to the database persist, even if there are system failures