What is primary key and alternate key?

Question

Primary keys - Contain one or more columns whose combined values uniquely identify every row in a table. Each table can have only one primary key. Alternate keys - Contain one or more columns whose combined values uniquely identify every row in a table. 8 дек. 2013 г.

What is primary and alternate key?

Primary key values should be unique and non-null. There can be multiple Super keys and Candidate keys in a table, but there can be only one Primary key in a table. Alternate keys are those Candidate keys that were not chosen to be the Primary key of the table.

What is an alternate key?

An alternate key (Alt key) is a key that is present on most computer keyboards and is considered a modifier key that can used similarly to the shift or control keys. In other words, the alternate key provides alternate input and operations when pressed in combination with other keys.

What is the primary key?

A primary key is the column or columns that contain values that uniquely identify each row in a table. A database table must have a primary key for Optim to insert, update, restore, or delete data from a database table.

What is alternative key and example?

All the keys which are not primary key are called an Alternate Key. Example: In this table, StudID, Roll No, Email are qualified to become a primary key. But since StudID is the primary key, Roll No, Email becomes the alternative key.

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