Few more questions

Q1. What is sysdate? Is it a pseudo column or system variable or a function?
Ans. It is a function.

Q2. Which one is faster Delete or Truncate?
Ans. Truncate is faster.

Q3. Can we use Decode function is PL/SQL without SQL statement?
Ans. No.

Q4. Can a primary key column have a null value?
Ans. No.

Q5. Can we call procedure using SQL statement?
Ans. No.

Q6. How many primary keys can be created per table?
Ans. Only one.

Q7. How many unique keys can be created per table?
Ans. More than one. As many as we want.

Q8. Using which Oracle package file operations can be done.
Ans. UTL_FILE.

Q9. Can we unwrap the Oracle program after wrapping it?
Ans. No.

Q10. Can we replace Decode function with Case statement in SQL statements?
Ans. Yes.

Q11. Can we replace If statement with Case statement in PL/SQL blocks?
Ans. Yes.

Q12. Why do we create indexes on tables?
Ans. To retrieve data from tables faster.

Q13. Can we undo the actions done by Truncate command?
Ans. No.

Q14. Does Oracle allow nested blocks in PL/SQL?
Ans. Yes.

Q15. Can we have a package without package body?
Ans. Yes.

Q16. What rights are required to work with Oracle Directory?
Ans. Read, Write & Execute.

Q17. What are the types of parameters that can be passed to a procedure or function?
Ans. In, Out & InOut.

Q18. Can we overload a procedure or function in Oracle?  How?
Ans. Yes. Using package overloading Can be done.

Q19. Can we have private procedures and functions in Oracle? How?
Ans. Yes. We can do this using package.

Q20. Can we return values from DML statements like Insert, Update & Delete?
Ans. Yes, Using returning… into… clause it can be done.

In case of any discrepancies or doubts do contact me.
Best of Luck Friends.