Select the activity that is most clearly part of the Database Administrator’s responsibility.
?
Performance tuning
?
Data modification
?
Data deletion
?
Data entry
Which normalisation transformation corresponds to "Eliminating partial key dependencies"?
?
unnormalised to 1NF
?
1NF to 2NF
?
2NF to 3NF
?
3NF to BCNF
Locking was introduced into databases so that
?
Keys can be provided to maintain security
?
All simultaneous transactions are prevented
?
Passwords can be provided to maintain security
?
Consistency can be enforced
A back-up and recovery regime should protect an organisation against:
?
incorrect data
?
corrupt media
?
insecure data
SQL has ———– types of commands
?
3
?
5
?
2
?
4
Transactions are often referred to in terms of ACID. Which one of the following is not part of the term ACID?
?
Atomic
?
Isolation
?
Durable
?
Complete
In ——- type of partitioning table is split on the basis of rows
?
Horizontal
?
Vertical
?
Parallel
?
None of the given
Which of the following is a good example of what is meant by?
“Serialisability”
?
All disk access happens one after another
?
The result of the transactions is the same as if the transactions went
one after another
?
The situation where the Lost Update problem exists
?
All transactions happen one after another
In two phase locking, when a transaction releases a lock, it may acquire additional lock.
???? True
???? False
The general purpose of data partitioning and placement is ——————.
???? Increasing workload
???? Decreasing workload
???? None of others
Transaction is executed as a whole or none. This property of transaction is called —————-
-.
???? Atomicity
???? Durability
???? Concurrency
RAID level 4 stripes data at byte level.
???? True
???? False
IN function helps reduce the need to use multiple AND conditions.
???? True
???? False
A relation that has no partial functional dependencies is in ___________ normal
form.
o 1NF
o 2NF
o 3NF
o none of above
User access to the database is supported by ______________schema.
o External schema
oo
Internal schema
Conceptual schema
o None of above
To keep duplicate values from being returned use the _________ keyword
o Distinct
o All
oo
None Of Above
Unique
De-normalization can increase the chance of errors and inconsistencies and can
force reprogramming if business rules change.
oo
False
True
A locking is a simple identifier that serves to identify each transaction.
o True
o False