a column that stores numbers that increment by one with each insertion

an acceptable candidate for a primary key, especially if the natural key is composed of several columns and thus very wide

an auto-incremented number that is assigned automatically to every new row inserted into the table, hence preventing any user typo and increasing the efficiency and speed of an indexed table

an exact-numeric column (e

a special column in SQL Server that can automatically take on values when an insert operation is done on the table

An Identity column is a column ( also known as a field ) in a database table that (1) uniquely identifies every row in the table, and (2) is made up of values generated by the database. This is much like an Auto Number field in Microsoft Access or a sequence in Oracle. Because the concept is so important in database science, all RDBMS systems implement some type of generated key, although each has its own terminology.