How to find candidate keys in this relation?

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In summary, a candidate key is a set of attributes in a relation that uniquely identifies each tuple. To determine candidate keys, functional dependencies of attributes must be analyzed. Relations can have multiple candidate keys, which are known as alternate or secondary keys. The primary key is a chosen candidate key used for identification, while a candidate key can potentially serve as a primary key. However, not all candidate keys are equally good and it is important to carefully consider and evaluate them before selecting a primary key.
  • #1
shivajikobardan
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Homework Statement
finding candidate keys
Relevant Equations
none
These are the FDs:
AB=>CD
C=>A
D=>B

My method of finding candidate keys is:

1) Look at RHS
2) Whatever isn't there could be a candidate key. (Find its closure).
But here everything is in RHS. So, I'm confused.
Can you share a better method to find candidate keys without getting too verbose(DBMS is too verbose).
 
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  • #2
my issue fixed after watching this video Qno.3
 

FAQ: How to find candidate keys in this relation?

What is a candidate key in a relation?

A candidate key is a minimal set of attributes that uniquely identifies each tuple in a relation. In other words, it is a combination of columns that can be used to uniquely identify a row in a table, and no subset of these columns can be used to uniquely identify a row.

How do you determine the candidate keys in a given relation?

To determine candidate keys, follow these steps: 1. Identify all possible attribute combinations.2. Check which combinations uniquely identify all tuples in the relation.3. Ensure that the combination is minimal, meaning no subset of the combination can also uniquely identify all tuples.4. The combinations that meet these criteria are the candidate keys.

What is the significance of candidate keys in database design?

Candidate keys are crucial in database design because they ensure that each record can be uniquely identified. This uniqueness is essential for maintaining data integrity, avoiding duplication, and establishing relationships between different tables through foreign keys.

Can a relation have more than one candidate key?

Yes, a relation can have multiple candidate keys. Each candidate key is an alternative way to uniquely identify tuples in the relation. When there are multiple candidate keys, one of them is typically chosen as the primary key.

What is the difference between a candidate key and a primary key?

A candidate key is any minimal set of attributes that can uniquely identify a tuple in a relation, while a primary key is a specific candidate key chosen by the database designer to uniquely identify tuples in the table. The primary key is often selected for its simplicity and efficiency in indexing and retrieval operations.

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