What is primary and alternate key?

Question

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 a 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 called 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 primary key and example?

A primary key is a column -- or a group of columns -- in a table that uniquely identifies the rows of data in that table. For example, in the table below, CustomerNo, which displays the ID number assigned to different customers, is the primary key. CUSTOMERS. CustomerNo.

Where is the alternate key?

On all keyboards, the Alt key is located in the bottom row, directly to the left of the space bar. In addition, English-language keyboards have a second Alt key (one to the left and one to the right of the space bar) to support ten-finger typing. English-language keyboards have two Alt keys.

Expert · Answer