Optimising Marksheet Database [closed]

Question

1. I am trying to design a database for mark sheet data of a school having different types of exams of different levels or class.
2. Is it possible to have single table where I can store data in string (array serialize PHP) and perform a search based on subjects easily (Maximum/Minimum/Average).

The table look something like this with bit variations-

Class 5

XXXXX ------ Math ----- Hindi ----- English
Amit -------- 10 ------- 20 ----------31
Alok -------- 10 ------- 20 ----------31

Class 8

XXXXX ------ Math ----- Hindi ----- English ---- Science
Amit -------- 10 ------- 20 ----------31 ----------20
Alok -------- 10 ------- 20 ----------31 ----------23

Using PHP's array serialize I will have marks data in string as

a:4:{s:4:"math";i:20;s:5:"hindi";i:30;s:7:"english";i:23;s:7:"science";i:10;}

Should I have separate table or can I have the condensed table so that database does not become too heavy with too many rows?

Answer 1

You really should not hide the data you want to do arithmetic inside any kind of structure.

Use a table with 4 columns: class, student, subject, score.

Then things like each student's avg score:

SELECT student,
       AVG(score)
    FROM tbl
    GROUP BY student;