Must we also create separate tables?

greetings

My book claims that for table to be in 1NF, we must:

• Eliminate remove repeating groups of data
• Create separate tables for each group of related data and identify each row with a unique column ( the primary key )

I know that for table to be in 1NF, we must remove repeating groups of data. But is it ( for relation to be in 1NF ) also required to create separate tables for each group of related data or is that just recommended and thus optional?

Say we have non-normalized table STUDENT:

STUDENT ( STUDENT#, STUDENT_NAME, SUBJECT1#, SUBJECT2#, SUBJECT1_NAME, SUBJECT2_NAME, TEACHER1_NAME, TEACHER2_NAME ) I realize best thing to do would be to create two tables:

STUDENT-SUBJECT ( STUDENT#, SUBJECT#, SUBJECT_NAME, TEACHER_NAME ) STUDENT ( STUDENT#, STUDENT_NAME) But would the following table also be considered in 1NF:

 STUDENT ( STUDENT#, STUDENT_NAME, SUBJECT, SUBJECT_NAME, TEACHER ) I realize the first option is much better, but my book gives an impression as if separate tables must also be created for related repeating groups of data in order for table to be 1NF compliant. Which doesn't make sense.

thank you Received on Sun Oct 26 2008 - 16:00:53 CDT