Database - The Relational Model and Normalization - Discussion
Discussion Forum : The Relational Model and Normalization - General Questions (Q.No. 5)
5.
The primary key is selected from the:
Discussion:
15 comments Page 1 of 2.
Uday kiran said:
1 decade ago
A primary key is taken from the Superkey, which is the set of candidate keys and other attributes. And the attributes other than.
Candidate key is not possible, so primary key is selected from candidate keys.
Candidate key is not possible, so primary key is selected from candidate keys.
Raku said:
1 decade ago
Composite keys consist of set keys.
Suraj R. said:
1 decade ago
Candidate key is a set of keys or attributes of an entity which are eligible to be a primary key at some time.
Jyoti said:
1 decade ago
Practically candidate key has no appearance in database so we choose primary keys from candidate keys for the practical implementation.
Sanjib said:
1 decade ago
Minimum super key called composit key.
But what is candidate key?
But what is candidate key?
Pooja manoja said:
1 decade ago
There may be more than one attributes in a relation, which recognizes a tuple uniquely. (each of attributes have a property of primary key) these attributes are called candidate day.
For example :in a student relation sid and regd are primary key.
For example :in a student relation sid and regd are primary key.
Madhur said:
1 decade ago
One of the candidate key is called primary key.
Sathish said:
1 decade ago
Only one key existence for a relation called candidate key that will become the primary key that will never reducible.
Sathi said:
1 decade ago
One of the minimal candidate key that derives all attributes of a relation.
SuchismitaM said:
1 decade ago
Candidate key contains no.of attributes which are the candidate to be the primary key (must contain unique value, must not be null). The keys other than primary key is known as non-prime key.
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