oracle auto_increment
snippet in sql

oracle create table auto generated primary key

user2164

-- For oracle 12c or later 
-- auto inc
create table t1 (
    c1 NUMBER GENERATED by default on null as IDENTITY,
    c2 VARCHAR2(10)
    );
-- More options for initial value and increment value
create table t1 (
    c1 NUMBER GENERATED ALWAYS as IDENTITY(START with 1 INCREMENT by 1),
    c2 VARCHAR2(10)
    );

oracle create auto increment column

user5111

CREATE TABLE animals (
     id MEDIUMINT NOT NULL AUTO_INCREMENT,
     name CHAR(30) NOT NULL,
     PRIMARY KEY (id)
);

INSERT INTO animals (name) VALUES
    ('dog'),('cat'),('penguin'),
    ('lax'),('whale'),('ostrich');

SELECT * FROM animals;
+----+---------+
| id | name    |
+----+---------+
|  1 | dog     |
|  2 | cat     |
|  3 | penguin |
|  4 | lax     |
|  5 | whale   |
|  6 | ostrich |
+----+---------+

oracle auto_increment

user5560

-- Use a sequence:
CREATE SEQUENCE id_seq START WITH 1;
INSERT INTO my_table (ID, VALUE) VALUES (id_seq.NEXTVAL, 'My value');