Oracle sequence - PK

CREATE TABLE Barva
(
    id_barva  NUMBER(8) NOT NULL,
    nazev     VARCHAR2(50) NOT NULL,
);

CREATE SEQUENCE seq_id_Barva INCREMENT BY 1 START WITH 1 MINVALUE 1 NOCYCLE;
 --INCREMENT BY 1 vzdy pricita 1 (ai muzou byt i zaporna)
 --START WITH 1 = zacne od 1
 --MINVALUE 1 = nejmensi hodnota
 --NOCYCLE = kdyz dopocita do maxima (10^27), tak nezacne od zacatku

INSERT INTO Barva (id_barva, nazev) VALUES (seq_id_barva.NEXTVAL, 'modra');
 --seq_id_barva.nextval = tim dostaneme PK vetsi, nez uz tam je


INSERT INTO Barva (id_barva, nazev) VALUES (seq_id_barva.NEXTVAL, 'zelena');

INSERT INTO Barva (id_barva, nazev) VALUES (seq_id_barva.NEXTVAL, 'stribrna');

INSERT INTO Barva (id_barva, nazev) VALUES (seq_id_barva.NEXTVAL, 'cervena');

SELECT * FROM Barva;

/*
ID_BARVA    NAZEV
1       modra
3       zelena
2       stribrna
4       cervena
*/