CREATE TABLE T(
  ID INTEGER GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY
);

/******************************************************************************/
/***                                 Tables                                 ***/
/******************************************************************************/



CREATE TABLE T (
    ID  INTEGER NOT NULL
);




/******************************************************************************/
/***                              Primary Keys                              ***/
/******************************************************************************/

ALTER TABLE T ADD PRIMARY KEY (ID);

RECREATE TABLE T(
  ID INTEGER GENERATED BY DEFAULT AS IDENTITY NOT NULL
);

ALTER TABLE T ADD PRIMARY KEY (ID);

SET AUTODDL ON;

RECREATE TABLE T(
  ID INT GENERATED BY DEFAULT AS IDENTITY,
  K INT
);

/* Тута заливаем данные пофиг на внутренний генератор */
/* Собственно копия */
INSERT INTO T(ID, K) VALUES(7, 1);
INSERT INTO T(ID, K) VALUES(10, 2);

COMMIT;

/* Стартуем внутренний генератор с 10 */
ALTER TABLE T ALTER COLUMN ID RESTART WITH 10;

/* Вешаем ПК */
ALTER TABLE T ADD PRIMARY KEY (ID);

/* Всё продолжает работать */

INSERT INTO T(K) VALUES(3);

COMMIT;

SELECT
    RF.RDB$GENERATOR_NAME
FROM
    RDB$RELATION_FIELDS RF
WHERE RDB$RELATION_NAME = 'T' AND RDB$FIELD_NAME = 'ID'