What is the difference between Candidate key and Superkey
Answers
Answer:
The candidate used for simple doors but the superkey is used for main foors
Answer:
Super Key:
Super Key is an attribute (or set of attributes) that is used to uniquely identifies all attributes in a relation. All super keys can’t be candidate keys but its reverse is true. In a relation, number of super keys are more than number of candidate keys.
Candidate Key:
Candidate key is a set of attributes (or attribute) which uniquely identify the tuples in a relation or table. As we know that Primary key is a minimal super key, so there is one and only one primary key in any relation but there is more than one candidate key can take place. Candidate key’s attributes can contain NULL value which oppose to the primary key.
Difference between super key and candidate Key:A super key is any combination of columns that uniquely identifies a row in a table. A candidate key is a super key which cannot have any columns removed from it without losing the unique identification property.