Chapter 5 – Modeling and Storage Principles

1. C is correct. Microsecond precision is used by default, consisting of six decimal places.
2. B is correct. DATE can operate up to second precision, whereas TIMESTAMP uses nanosecond precision.
3. C is correct. DATE and TIMESTAMP cannot hold time zone references. Using TIMESTAMP with a local time zone incorporates the shift between the server and client directly into the value itself during retrieval and processing.
4. A is correct. There is a TIMESTAMP keyword followed by the element value definition. There is no explicit mapping definition, so the order of elements must apply the predefined format.
5. D is correct. SYSDATE and CURRENT_DATE provide the DATE data type. systimestamp provides the database’s time zone and localtimestamp provides the client side’s time.
6. D is correct. Oracle provides the number of days elapsed when two DATE values are subtracted.
7. A is correct. Oracle provides INTERVAL DAY TO...