COMPUTER SCIENCE AND ENGINEERING
DATABASE MANAGEMENT SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Foreign key
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Surrogate key
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Primary key
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Secondary key
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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: -That country column in the customer table would be a foreign key. A secondary key on the other hand is just a different column in the table that you have used to create an index (which is used to speed up queries). Foreign keys have nothing to do with improving query speeds.