Thus, the super key is the super set, the candidate key is the subset, and the primary key is the sub-subset of the superkey. Next TopicPrimary Key in DBMS For Videos Join Our Youtube Channel:Join Now Send your Feedback to feedback@javatpoint.com ...
The relationship of the candidate key and primary key is easier to describe — basically, a relational database can have more than one candidate keys, but only one of these candidate keys will be the primary key that will be primarily used to identify each record uniquely. The best way to ...
Unlock the secrets of Candidate Keys in DBMS! Discover how they ensure database integrity & boost your data management skills. Read now!
{Roll_no, Name, Registration_no}:This key cannot be considered as a candidate key because when we take the subset of this key we get three attributes i.e Roll_no, Registration_no and Name. Two of these attributes i.e Roll_no and Registration_no are the candidate key. So, it is not...
Example 1:Give R(X, Y, Z, W) and Set of Functional Dependency FD = { X → Y, Y → Z, Z → X}. The question is to calculate the candidate key and no. of candidate key in above relation R using a given set of FDs.
Every candidate key is a super key but, every super key may or may not be a candidate key. There many other distinguishing factors between super key and candidate key, which I have briefly discussed in the comparison chart below.