PL/SQL 十问

1，Char, varchar and varchar2 区别？

2，Outter join & Inner join 区别？

3，什么是Cursor, 如何使用？

4，When/where does a Transaction begin?

5,What is a Foreign key?

6,Can we Rollback changes made by a 'Truncate'?

7,Difference between Function  & Procedure?

8,What is a Trigger, Two Trigger, same condition, which one go first?

9,Emp (EMP_ID, SALARAY, DEP_ID)
Write a SQL to list highist salary of each department.

10, What is RowNum? Can we use a clause '......where RowNum = n' to get the NO. n record?