Consider the instance of the STUDENT relation shown in the following t

1.	Consider the instance of the STUDENT relation shown in the following table Assume Reg_no as the primary key.(a) Identify the candidate keys and alternate keys in the STUDENT relation (b) How are the primary key and the candidate key-related? Reg_no Name Batch Result Marks101SachinSciencePass480103FathimaHumanitiesFall200106FathimaCommercePass360108BincySciencePass300
Answer» (a) Reg_no and Reg_no+Batch are the candidate keys. We set Reg_no as the primary key hence Reg_no+Batch is the alternate key (b) Candidate Key : It is a set of attributes that uniquely identifies a row. There may be more than candidate key and may be a combination of more than one attribute. Primary Key: A primary key is one of the Candidate Keys. It is a set of one or more attributes that can uniquely identify tuples in a relation.

Consider the instance of the STUDENT relation shown in the following table Assume Reg_no as the primary key.(a) Identify the candidate keys and alternate keys in the STUDENT relation (b) How are the primary key and the candidate key-related? Reg_no Name Batch Result Marks101SachinSciencePass480103FathimaHumanitiesFall200106FathimaCommercePass360108BincySciencePass300

Answer»

(a) Reg_no and Reg_no+Batch are the candidate keys. We set Reg_no as the primary key hence Reg_no+Batch is the alternate key

(b) Candidate Key :

It is a set of attributes that uniquely identifies a row. There may be more than candidate key and may be a combination of more than one attribute.

Primary Key:

A primary key is one of the Candidate Keys. It is a set of one or more attributes that can uniquely identify tuples in a relation.