7. Compare Truncate and Delete Commands
Solution: Both can be used to delete all records in the table. The difference is that Truncate is DDL operation, it moves HWK, does not require rollback segment. And DELETE is DML operation, which requires Rollback Segment and spends longer.
8. Reasons for using indexes
Answer: Quick access to Data Block
9. Given the two tables in Star Schema and their respective data
Answer: Fact Tables and Dimension Tables. Fact Table contains a large amount of information and Dimension Tables store information for some attributes of Fact Table.
10. What index is needed on Fact Table?
Answer: Bitmap Index)
11. Give two related constraints?
Answer: Primary key and foreign key
12. How to rebuild a master table without affecting the child table
Solution: The foreign key of the sub-table is enforced, reconstructed the master table, and the foreign key is activated.
13. Interpret the difference between archiving and non-archive mode and their respective advantages and disadvantages
Answer: Archiving mode means you can back up all database transactions and return to any point in time. In contrast, the non-invasive mode cannot be recovered to any time point. However, non-archiving patterns can bring a little increase in database performance.
