How do I find the candidate key in SQL?

How do I find the candidate key in SQL?

  1. The first step in the process of finding a normal form and decomposing a relation is to find the candidate. keys.
  2. R = (ABCDE), F = {A -> C, E -> D, B -> C}
  3. R = ABCDE, F = {A -> BE, C -> BE, B -> D}
  4. R = ABCDEF, F = {A -> B, B -> D, C -> D, E -> F}
  5. R = ABCD, F={AB -> C, BC -> D, CD -> A}
  6. R = ABCD, F={A -> BCD, C -> A}

How do I find the candidate key in a table?

Candidate Key is minimal set of attributes of a relation which can be used to identify a tuple uniquely. For Example, each tuple of EMPLOYEE relation given in Table 1 can be uniquely identified by E-ID and it is minimal as well. So it will be Candidate key of the relation.

How do you find the candidate key from functional dependencies?

The candidate key can be determined from given set of functional dependency in a relation. It is an attribute or minimal set of attributes whose closure is set of all attributes in a relation. = ABCD. Find the candidate keys in above relation.

How do you choose a candidate key?

Definition of Candidate Key in DBMS: A super key with no redundant attribute is known as candidate key. Candidate keys are selected from the set of super keys, the only thing we take care while selecting candidate key is that the candidate key should not have any redundant attributes.

Which is an example of a candidate key?

A candidate key is defined as a set of minimal attributes that can identify each tuple uniquely in the given relation. Examples. How to find Candidate Keys- To find candidate keys of any given relation, we follow the discussed steps.

How to implement candidate key in any mysql table?

Therefore, candidates for Primary Key is called Candidate Key. To implement candidate key in MySQL, set more than one column as unique key. These keys would qualify for candidate key as in the below syntax −

How to find the candidate key for R?

Consider the relation scheme R (E, F, G, H, I, J, K, L, M, N) and the set of functional dependencies- What is the key for R? Also, determine the total number of candidate keys and super keys. Determine all essential attributes of the given relation. So, attributes E, F and H will definitely be a part of every candidate key.

Can a candidate key be a Super key?

Note: A candidate key is always a super key but vice versa is not true. Q. Finding Candidate Keys and Super Keys of a Relation using FD set The set of attributes whose attribute closure is set of all attributes of relation is called super key of relation. For Example, the EMPLOYEE relation shown in Table 1 has following FD set.