The following SQL statement defines the "Personid" column to be an auto-increment primary key field in the "Persons" table:
Personid int IDENTITY(1,1) PRIMARY KEY,
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Age int
);
The MS SQL Server uses the IDENTITY keyword to perform an auto-increment feature.
In the example above, the starting value for IDENTITY is 1, and it will increment by 1 for each new record.
Tip: To specify that the "Personid" column should start at value 10 and increment by 5, change it to IDENTITY(10,5).
To insert a new record into the "Persons" table, we will NOT have to specify a value for the "Personid" column (a unique value will be added automatically):
VALUES ('Lars','Monsen');
The SQL statement above would insert a new record into the "Persons" table. The "Personid" column would be assigned a unique value. The "FirstName" column would be set to "Lars" and the "LastName" column would be set to "Monsen".
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