The

The `SET NOT NULL` and `DROP NOT NULL` Clauses

The SET NOT NULL clause adds a NOT NULL constraint on an existing table column.Contrary to definition in CREATE TABLE, it is not possible to specify a constraint name.

Note

The successful addition of the NOT NULL constraint is subject to a full data validation on the table, so ensure that the column has no nulls before attempting the change.

An explicit NOT NULL constraint on domain-based column overrides domain settings.In this scenario, changing the domain to be nullable does not extend to a table column.

Dropping the NOT NULL constraint from the column if its type is a domain that also has a NOT NULL constraint, has no observable effect until the NOT NULL constraint is dropped from the domain as well.

The `COMPUTED [BY]` or `GENERATED ALWAYS AS` Clauses

The data type and expression underlying a computed column can be modified using a COMPUTED [BY] or GENERATED ALWAYS AS clause in the ALTER TABLE ALTER [COLUMN] statement.Conversion of a regular column to a computed one and vice versa is not permitted.

The

The SET NOT NULL and DROP NOT NULL Clauses

The COMPUTED [BY] or GENERATED ALWAYS AS Clauses

The `SET NOT NULL` and `DROP NOT NULL` Clauses

The `COMPUTED [BY]` or `GENERATED ALWAYS AS` Clauses