Only UNIQUE or PRIMARY KEY constraints can be created on computed columns, while CHECK, FOREIGN KEY, and NOT NULL constraints require that computed columns be persisted.

Error Message:
Msg 8183, Level 16, State 1, Line 5
Only UNIQUE or PRIMARY KEY constraints can be created on computed columns, while CHECK, FOREIGN KEY, and NOT NULL constraints require that computed columns be persisted.

Severity level:
16.

Description:
This error message appears when you try to use another constraint type than a PRIMARY KEY or UNIQUE constraint for a computed column.

Consequences:
The SQL statement cannot be parsed and further execution is stopped.

Resolution:
Errors of the Severity Level 16 are generated by the user and are corrigible by the user. The statement cannot be executed this way. You must remove the constraint or persist the column.

Versions:
All versions of SQL Server.

Example(s):
USE tempdb;
IF OBJECT_ID('t', 'table') > 0
 DROP TABLE t
GO
CREATE TABLE t
(
 c1 INT,
 c2 AS c1 * 4 NOT NULL
)

Remarks:
In the above example we try to create a NOT NULL constraint on the computed column c2. This raises the error.