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.
Siddhu said:
1 decade ago
A Candidate Key can be any column or a combination of columns that can qualify as unique key in database. There can be multiple Candidate Keys in one table.
Each Candidate Key can qualify as Primary Key. Primary Key " A Primary Key is a column or a combination of columns that uniquely identify a record.
Each Candidate Key can qualify as Primary Key. Primary Key " A Primary Key is a column or a combination of columns that uniquely identify a record.
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.
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.
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.
Karthik said:
1 decade ago
Candidate key is a combination of two or more attributes (emp name, emp street), from which primary key will be derived, primary key derived from set of candidate keys.
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.
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.
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.
Elias joseph said:
8 years ago
Minimum super key is called candidate key so primary key is the part of the candidate key.
Rahul said:
1 decade ago
Guys. Does candidate or unique key has got the same property or features of Primary key?
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers