Alter Table Nullable Column. To modify a column of a table you need to specify the column name table name and action that you want to perform. First example the constraints with the desc SQLPlus command.
Thanks Craigbert Jan 11 11 1. The NOT NULL constraint enforces a column to NOT accept NULL values. Verify Altered Nullability Once the alteration to your column is made it is a good practice to verify the column no longer allows any NULL values by running a simple INSERT test and trying to insert a new record with the NULL value in the altered column.
To do this you need to remove the NOT NULL constraint from the column by using the ALTER TABLE statement as below.
ALTER TABLE table_name ALTER COLUMN col_name data_type NOT NULL. Next you can alter the table column to make it allow NULL. Alter the table to add the column as NULLable 2. The query is as follows.
