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* = PK (Primary Key)
@ = FK {foreign Key)
^ = Unique
1NF example
employee ( Name*, Phone )
Name*, Phone
Jim, 320-234-8546,320-583-8490
Jeff, 123-456-7890
Add an id field so we are not using text like the name as the PK.
employee ( id*, Name, Phone )
id*, Name, Phone
1, Jim, 320-234-8546,320-583-8490
2, Jeff, 123-456-7890
Remove non-atomic values. Do this by repeating a row and leaving a different value in each row.
This may make the PK not unique for now.
employee ( id*, Name, Phone )
id*, Name, Phone
1, Jim, 320-583-8490
1, Jim, 320-234-8546
2, Jeff, 123-456-7890
If you have repeating data, put it in a new table and also create another table for the rest of the data.
employee ( id*, Name )
id*, Name
1, Jim
2, Jeff
employeephone ( id*@, Phone* )
id*@, Phone*
1, 320-583-8490
1, 320-234-8546
2, 123-456-7890
2NF example
Student_Grade_Report (StudentNo*, StudentName, Major, CourseNo*, CourseName, InstructorNo, InstructorName, InstructorLocation, Grade)
For this table, the StudentName and Major only depend on the StudentNo (not the CourseNo).
Student (StudentNo*, StudentName, Major)
StudentCourse (StudentNo*, CourseNo*, CourseName, InstructorNo, InstructorName, InstructorLocation, Grade)
For the StudentCourse table, only the Grade is dependant on both the StudentNo and CourseNo.
So put the rest of the data in another table.
Student (StudentNo*, StudentName, Major)
CourseGrade (StudentNo*, CourseNo*, Grade)
CourseInstructor (CourseNo*, CourseName, InstructorNo, InstructorName, InstructorLocation)
3NF example
CourseInstructor (CourseNo*, CourseName, InstructorNo, InstructorName, InstructorLocation)
Dependencies are:
CourseNo -> CourseName, InstructorNo, InstructorName, InstructorLocation
InstructorNo -> InstructorName, InstructorLocation
Since InstructorNo determines other attributes they should be placed in another table.
Course (CourseNo*, CourseName, InstructorNo@)
Instructor (InstructorNo*, InstructorName, InstructorLocation)