1. Database recovery restores the database from current state to previous state which is triggered by a critical error caused by ___________ or ____________.
A. hardware error, software error
2. The database in the grocery has T1 transaction that is read and the database reads the same row T2 at the same time producing different results, this is a result of ______________________.
a. non repeatable read
3. You decide to use the __________________ phase of the optimistic approach in the concurrency method to validate the transaction to ensure that the changes made will not affect the integrity and consistency of the database.
a. validation phase
4. You decide to use database transaction recovery for data in the transaction log to recover a database from an inconsistent state to a consistent state which include these four concepts ___________,___________ ,______________ and ______________.
A. write-ahead log protocol, redundant transaction logs, buffer, checkpoint
5. The DBMS uses the information stored in the _____ log for a recovery requirement triggered by a ROLLBACK statement, a program’s abnormal termination, or a system failure such as a network discrepancy or a disk crash.
A. transaction
6. Database transaction _____ restores a database from an inconsistent state to a previously consistent state.
A. recovery
7. You develop a single-user database system that only one transaction is executed at a time. These two isolation properties automatically ensure the integrity of the database.
A.atomicity and isolation
8. _____ occurs when a transaction accesses data before and after one or more other transactions finish working with such data.
A. Inconsistent retrieval
9. In the optimistic approach, during the _____ phase, changes are permanently applied to the database.
A. write
10. _____ means that data used during the execution of a transaction cannot be used by a second transaction until the first one is completed.
A. Isolation
11. What type of analyzer would you use if you are trying to analyze the SQL query and find the most efficient way to access the data?
A. query optimizer
12. What type of cache, used for temporary storage, are for ORDER BY and GROUP BY?
A. sort
13. When using databases from the performance point of view, what type of database eliminates disk access bottlenecks?
A. in-memory
14. Bitmap indexes tend to use less space than a _____ because they use bits instead of bytes to store their data.
A. B-tree index
15. If you use multiple AND conditions, write the condition most likely to be _________ first.
A. False
16. If you are using the raid levels, what type of raid level is used for writing the same data blocks to separate drives?
A. mirroring
17. When setting optimizer hints, _____ instructs the optimizer to minimize the overall execution time, that is, to minimize the time it takes to return the total number of rows in the query result set. This hint is generally used for batch mode processes.
A. ALL_ROWS
18. What type of index would you use if you need an index based on a specific SQL function or expression?
A. function-based
19. How can you write this phrase NOT (C_COST > 20.00) without using NOT?
A. C_COST < = 20.00.
20. What type of index guarantee(s) that the number of index block accesses is equal to the level of the index structures?
A. B-tree