Hello Friends, In this blog post(What is a candidate key in DBMS) we are going to discuss what is a candidate key in DBMS. An attribute or a column in a table that can identify a full tuple or row records in a data table is considered a candidate key.
Now the question is that all the other keys like primary, alternate, super, unique, and foreign are also used to uniquely identify a tuple value so are they all candidate keys?|What is a candidate key in DBMS|
Yes, any key that is capable of identifying a tuple value is considered a candidate key though they could also have their features like a primary key does not allow the entry of a null value. Whereas a unique key allows doing the same|What is a candidate key in DBMS|
Within this blog(What is a candidate key in DBMS), we will see what is candidate key explained with an example. What are the candidate key and primary key? What is the use of the candidate key? What is the difference between the super key and the candidate key?…
… Candidate key vs primary key, Super key, and candidate key, Candidate key example, What is Super key, Alternate key, Super key example|What is a candidate key in DBMS|
What are the candidate key and primary key?
Both keys can uniquely identify the tuple value or full records. The primary key is also a candidate key. But the primary key is a candidate key with no null value. and in a single table, there could be only one primary key.
The candidate key may hold the null value. In a single database table, there could be more than one candidate key.
What is the use of the candidate key?
The purpose of the candidate key is to select the primary key from the set of all candidate keys.
There must be one candidate key in the table that could be considered the primary key of the table to uniquely identify the records.
What is the difference between the super key and the candidate key?
Candidate keys are the subset of the super keys. All candidate keys are super keys but all super keys may or may not be the candidate keys.
The candidate key is the minimal set of attributes to uniquely identify the tuple value.
Where the super key is the set of one or more columns or attributes to uniquely identify the tuple value.
What is the candidate key explain with an example.
With the help of the below image, you can understand the whole scenario of all the keys.
In very simple language, we can say that a candidate key is a generalized concept to has a unique value to identify the whole row record. thus any DBMS key fulfilling this criterion will be a candidate key.
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Conclusion:
Every key that can easily identify a tuple value with the property of uniqueness, which means that every tuple has a unique value for a particular attribute value is called a candidate key. There may be one or more candidate keys in the database table|What is a candidate key in DBMS|
Using this blog we have explored the Candidate key vs primary key, Super key, and candidate key, Candidate key example What is a candidate key in DBMS, Alternate key, and Super key example?
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