Web-based examination system

Hi guys needing your help. I’m currently developing an examination system. I’m having problems implementing the following on my system.

-students would have random order of questions for the different types of test (e.g.: multiple choice, identification etc.) on a certain examination.
-students could view the questions one-by-one, while having the option to answer the item, skip or answer the questions on the other examination types.

could you give me some ideas how will I be able to implement/handle this or if possible a better idea on implementing this kind of system.

Thanks in advanced. (: Hope you could help me…

Are you storing your questions in a database?

Yes I am. I basically have three tables for it.

Exam -holds data about the exam
Item- holds the questions for the exam and also the answer.
Choices- for exams that needs choices.

Exam
exaID PK
insID FK - instructor ID
claID FK - Class ID
exaSchedule
exaRoom
exaAccessCode
exaDuration
exaTerm
exaStat

Item
iteID PK
typID FK -type of exam
iteQuestion
iteAnswer
examID FK

Choices
choID PK
iteID FK
choice

I also store the answers of the students on this table

examAnswers
iteID FK
stuID FK
exaaAnswer