FUNDAMENTALS OF COMPUTER

Detailed explanation-1: -A primary key is the field in a database that is the primary key used to uniquely identify a record in a database. A secondary key is an additional key, or alternate key, which can be use in addition to the primary key to locate specific data.

Detailed explanation-2: -The main purpose of the primary key is faster data retrieval.

Detailed explanation-3: -Secondary keys are also called alternate keys. They uniquely identify rows in a table and thus can be used alternatively as primary keys.

Detailed explanation-4: -Secondary keys are used to view records in an order that is different from the order defined by the primary key fields.

Detailed explanation-5: -Secondary Key-Only one of the candidate keys is selected as the primary key. The rest of them are known as secondary keys. Foreign Key-A foreign key is an attribute value in a table that acts as the primary key in another table. Hence, the foreign key is useful in linking together two tables.