Question

I need your help with my database design. I’m trying to develop a Result Application whereby teachers will be able to compute the results of various students in 5 different levels (Year 1-5). Also all students are required to take some amount of courses as they progress, and no student will be registered twice and no student will be able to register for two courses either at there present level of in the future.

I have the following tables in my:

Database: RESULTS
-----------------

Table: STUDENTS
        This takes care of the student registration validation 
        and avoiding duplication)
 - studentID
 - first_name
 - last_name
 - other_name

Table: COURSES
        This is preloaded to the database, but it can be edited 
        to suit the needs of the user
 - courseID
 - course_code
 - course_title
 - course_unit

Table: SCORES
        This takes entries from the STUDENTS and COURSES table, 
        so there wouldn't be any occurrence of a student taking 
        the same course more than once
 - scoresID
 - courseID
 - studentID
 - semesterID
 - score
 - grade
 - remarks

The YEAR tables are what I’ve got concerns about, they are supposed
to be for all the courses meant for Year 1 to 5 respectively,
so that courses registered by any student will go
into the respective year.

Tables: YEAR1, YEAR2, YEAR3, YEAR4, YEAR5
 - courseID
 - studentID
 - score
 - grade
 - remarks

Table: SEMESTER
        This takes care of the semester courses identity.
 - semesterID 
   (year1_semester1, year1_semester2, 
    year2_semester1, year2_semester2, 
    year3_semester1, year3_semester2, 
    year4_semester1, year4_semester2, 
    year5_semester1, year5_semester2)

In every table, the tableID is unique.

Please tell me what else should I add to or remove from the database design.

Answer 1

Tables STUDENTS and COURSES are OK.

In case of SCORES the column scodeID is probably not necessary as you can use courseID and studentID columns as composite primary key.
A question regarding this table: will the students be able to take an exam/test twice (e.g. first failed)? If yes, should both scores be recorded or only the final score? The current design does not allow more than one score.

I am not sure if SEMESTERS table is really necessary. Since you do not plan to store additional information about a year/semester pairs (i.e. only year and semester would be stored, no description or other details), you could simply use two numeric columns in SCORES (instead of semesterID): year and semester. Both of these would have a check constraint on them; the one on yearwould allow only values 1 to 5; the other on semester would allow only 1 and 2. The separate table would be useful only if you wanted to add more details to the semesters.

The YEAR1 … YEAR5 tables: I think there should be only one table with a year column to allow you to separate the years. Having multiple tables to store the same records structure will lead to a lot of extra coding.
And I am not sure if this/these tables is/are necessary at all. The information that this/these tables would store is already stored in the SCORES table. If you rename the SCORES table to COURSES_TAKEN and leave the score and grade columns initially empty (to show that the students took the course but do not yet take the exam/test) you can have the functionality of SCORES and YEARx tables in one.

Finally, you wrote: “no student will be registered twice and no student will be able to register for two courses either at there present level or in the future“. One thing I surely learned during my career is that words like “never” and “always” are not valid in the long term. If you develop a good solution and the end users like it, they will want a lot of new things and changes it; even new things and changes of which that they previously stated that they will never need. So, always try to keep your design flexible to be able to handle any crazy new requests easily.