Unfortunately oracle doesnot support auto_increment like mysql does. You need to put a little extra effort to get that.
say this is your table -
CREATE TABLE MYTABLE (
ID NUMBER NOT NULL,
NAME VARCHAR2(100)
CONSTRAINT "PK1" PRIMARY KEY (ID)
);
You will need to create a sequence -
CREATE SEQUENCE S_MYTABLE
START WITH 1
INCREMENT BY 1
CACHE 10;
and a trigger -
CREATE OR REPLACE TRIGGER T_MYTABLE_ID
BEFORE INSERT
ON MYTABLE
REFERENCING NEW AS NEW
FOR EACH ROW
BEGIN
if(:new.ID is null) then
SELECT S_MYTABLE.nextval
INTO :new.ID
FROM dual;
end if;
END;
/
ALTER TRIGGER "T_MYTABLE_ID" ENABLE;