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Candidate keys in a relational database are columns or sets of columns that can uniquely identify records in a table and serve as potential primary keys. However, only one of them is chosen as the primary key, while the others remain as unique identifiers for backup or alternate purposes. For instance, in an employee database, both employee_id and social_security_number could be candidate keys, but only one is chosen as the primary key. The other remains a unique identifier, fulfilling the role of a candidate key. Candidate keys are essential in database design to ensure flexibility in record identification without data redundancy. They play a critical role in normalization by allowing tables to maintain unique records through various unique identifiers, ensuring data integrity and avoiding duplication. Option A - This option describes a scenario involving the selection of a primary key but does not capture the purpose of a candidate key, which exists as an alternative unique identifier. Option B - Foreign keys are used to create referential integrity by linking tables but are distinct from candidate keys, as they do not serve as unique identifiers within the original table. Option D - Composite keys, while related to unique identifiers, differ in function from candidate keys, as they are combinations of multiple fields that uniquely identify records. Option E - Normalization is achieved through functional dependencies and is not directly related to the role of candidate keys, which ensure uniqueness but are not involved in dependency elimination.
The largest general insurance company in the world by revenue is:
The first private health insurance company in India was:
A policy that covers the loss of baggage during travel is:
Which among these is not a type of General Insurance plans?
I. Motor Insurance
II. Marine Insurance
III. Health Insurance
A motor insurance cover note is valid for how many days?
An endorsement added to an insurance policy, or clause within a policy, that provides additional coverage for risks other than those in a basis policy i...
Who is the chairman of 15th Finance Comission?
What is NOT a common express condition in an insurance policy?
Which is not a General Insurance company?
Consider the following statement:
I. NCB is given to the insured and not to the insured vehicle.
II. On transfer of the vehicle, the ...