Oracle - Autoincrement con Store Procedure con pl sql

CREATE TABLE  TEST_TABLE_INCREMENTAL

("ID" NUMBER(10,0) GENERATED  ALWAYS AS IDENTITY MINVALUE 1

MAXVALUE 9999999999999999999999999999

INCREMENT BY 1 START WITH 1 CACHE 20  NOORDER  NOCYCLE  NOT NULL ENABLE,

"NAME" VARCHAR2(15)

 )

create table alumno(

id_alumno number primary key  GENERATED  ALWAYS AS IDENTITY MINVALUE 1

MAXVALUE 9999999999999999999999999999

INCREMENT BY 1 START WITH 1 CACHE 20  NOORDER  NOCYCLE  NOT NULL ENABLE,

nombre_alumno varchar2(20)

);