Normalization in database systems | Steps for Normalization| Concept of Normalization | Do's and Dont's of Normalization | Normal forms | Partial dependencies | Transitive dependency | Key tips to remeber | Tricks to break a table

1. NORMALIZATION
KEY TIPS TO REMEMBER
ENSURITY OF UNIQUE KEYS
REMOVE PARTIAL AND TRANSITIVE
DEPENDENCIES
USE SEPARATE TABLES FOR REPEATING DATA
1
2
3

2. STEPS FOR NORMALIZATION:

3. STEP-1: REMOVE REPETITIONS(1 NF)

4. STEP-2: REMOVE PARTIAL DEPENDENCIES(2 NF)
ALL NONKEY ATTRIBUTES SHOULD DEPEND ON THE WHOLE PRIMARY
KEY NOT PART OF IT. Let’s analyze:
•StudentName, CourseID, CourseLength depend only on StudentID.
•UnitName, Lecturer depend only on UnitCode.

5. STUDENT_UNIT IS MADE BECAUSE IF WE TRY TO INCORPORATE IT
INTO THE STUDENT TABLE IT WILL CAUSE REDUNDANCY BEACAUSE
FOR ONE VALUE OF STUDENT_ID THERE ARE TWO VALUES OF
UNIT_CODE
KEY TIP:

6. STEP-3: REMOVE TRANSITIVE
DEPENDENCIES (3 NF)
Non-key attributes should only depend on the primary key.
Now check each table:
•Student: StudentID StudentName, CourseID, CourseLength
→
But we can see: CourseID CourseLength
→
So, there’s a transitive dependency.

7. STEP-3: REMOVE TRANSITIVE
DEPENDENCIES (3 NF)
AFTER REMOVAL OF TRANSITIVE DEPENDENCY:

8. STEP-3: REMOVE TRANSITIVE
DEPENDENCIES (3 NF)
AFTER REMOVAL OF TRANSITIVE DEPENDENCY:

9. FINAL NORMALIZED TABLES:
1. Student(StudentID, StudentName, CourseID)
2. Course(CourseID, CourseLength)
3. Unit(UnitCode, UnitName, Lecturer)
4. Student_Unit(StudentID, UnitCode)