How can I drop a “not null” constraint in Oracle when I don't know the name of the constraint?

Question

I have a database which has a NOT NULL constraint on a field, and I want to remove this constraint. The complicating factor is that this constraint has a system-defined nam

Answer 1

If constraint on column STATUS was created without a name during creating a table, Oracle will assign a random name for it. Unfortunately, we cannot modify the constraint directly.

Steps involved of dropping unnamed constraint linked to column STATUS

1. Duplicate STATUS field into a new field STATUS2
2. Define CHECK constraints on STATUS2
3. Migrate data from STATUS into STATUS2
4. Drop STATUS column

5. Rename STATUS2 to STATUS

   ALTER TABLE MY_TABLE ADD STATUS2 NVARCHAR2(10) DEFAULT 'OPEN'; ALTER TABLE MY_TABLE ADD CONSTRAINT MY_TABLE_CHECK_STATUS CHECK (STATUS2 IN ('OPEN', 'CLOSED')); UPDATE MY_TABLE SET STATUS2 = STATUS; ALTER TABLE MY_TABLE DROP COLUMN STATUS; ALTER TABLE MY_TABLE RENAME COLUMN STATUS2 TO STATUS;