Hey guys, I'm having an issue understanding how to write a table that uses an id and another id which both have dual keys. What I mean by dual keys is they use primary key and foreign keys.
Example:
Table Name = Enrollment
Column Name = Sid, Csecid, Grade
Data Type = NUMBER, NUMBER, NUMBER
Lgth = w/e,w/e,w/e
PK = Sid, Csecid
FK = Sid, Csecid
Check = A,B,C,D,F,I
I'm having issues writing it out in SQL code such as Create Table Enrollment... etc
Just refer to the standard EMP and DEPT tables of SCOTT schema.
Try to analyze that , you will be able to write your own.
Primary Keys SHOULD be a single column with unique values.
Foreign Keys SHOULD be a single column refering to Primary Keys.
If you want uniqueness of multiple columns (in a single record), create a Unique Key.
Keep it simple!
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