1. List and describe three criteria that should be considered when selecting a primary key for a table:

B. In Oracle, what is the difference between the CURRENT_DATE function and the SYSDATE function?

C. What is wrong with the statement Gender is defined as char(1)

ALTER TABLE patient ADD CONSTRAINT p_gender_cCHECK (GENDER IN (NULL, F, M));

2. give more explanation :

Assume that the table VEHICLE has the following data:

V_ID	MAKE	COST_PER_DAY
9090	BMW	100.00
9111	FIAT	100.00
9191	FORD	51.00
9192	FORD	88.00
1001	NISSAN	40.00

How many rows will be deleted by the following SQL statements:

a. DELETE FROM VEHICLE WHERE UPPER(MAKE) IN (NISSAN,FORD); ______?

b. DELETE FROM VEHICLE WHERE MAKE = NISSAN AND MAKE = FORD; ______?

c. DELETE FROM VEHICLE WHERE MAKE = NISSAN OR MAKE = FORD; ______?

d. DELETE FROM VEHICLE; ______?

e. Write SQL statement to decrease the cost per day by 15% for three makes of cars: HONDA, NISSAN, and BMW.