Final answer:
The question is about SQL commands to retrieve the current date and time in a DBMS: CURRENT_TIME/NOW() for time, CURRENT_DATE for date, and CURRENT_TIMESTAMP for both date and time.
Step-by-step explanation:
The question you're asking seems to be about the different SQL commands that are used to retrieve the current date and time in a database management system (DBMS). Each command you mentioned serves a different purpose:
- CURRENT_TIME or NOW() are used to obtain the current time.
- CURRENT_DATE is used to retrieve the current date without the time.
- CURRENT_TIMESTAMP fetches both the current date and time.
These functions are commonly used in SQL queries to record the time-stamps of data records or to make temporal comparisons or calculations within a DBMS. Selecting the correct function depends on the specific requirement whether you need the time, date, or both in your query.