What is alternate keys in table?

Question

ALTERNATE KEYS is a column or group of columns in a table that uniquely identify every row in that table. A table can have multiple choices for a primary key but only one can be set as the primary key. All the keys which are not primary key are called an Alternate Key. 19 февр. 2022 г.

What are alternative keys?

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.

How many alternate keys can be there in a table?

There can be one or more alternate keys in a table and contain NULL values unless it is mentioned to be NOT NULL explicitly. The UNIQUE keyword is used to define the alternate key, which indicates the value must be unique.

How do you define alternate key in SQL?

ALTERNATE Keys in SQL are defined using the SQL constraint UNIQUE. UNIQUE(col_name(s)) col_name(s): The name of the column(s) in the table which need to be unique.

Expert · Answer