How to create id with AUTO_INCREMENT on Oracle?

Question

It appears that there is no concept of AUTO_INCREMENT in Oracle, up until and including version 11g.

How can I create a column that behaves like auto increment in Or

Answer 1

it is called Identity Columns and it is available only from oracle Oracle 12c

CREATE TABLE identity_test_tab
(
   id            NUMBER GENERATED ALWAYS AS IDENTITY,
   description   VARCHAR2 (30)
);

example of insert into Identity Columns as below

INSERT INTO identity_test_tab (description) VALUES ('Just DESCRIPTION');

1 row created.

you can NOT do insert like below

INSERT INTO identity_test_tab (id, description) VALUES (NULL, 'ID=NULL and DESCRIPTION');

ERROR at line 1: ORA-32795: cannot insert into a generated always identity column

INSERT INTO identity_test_tab (id, description) VALUES (999, 'ID=999 and DESCRIPTION');

ERROR at line 1: ORA-32795: cannot insert into a generated always identity column

useful link