i learnt this

Creating a procedure in PL-SQL: Firstly, we create a table, a sequence for the primary keys and a trigger to handle the value of primary key. =========================== DROP TABLE DUMMY_TABLE; CREATE TABLE DUMMY_TABLE( DUMMY_ID INTEGER, TIME_DELAY INTEGER ); ALTER TABLE DUMMY_TABLE ADD( CONSTRAINT DUMMY_PK PRIMARY KEY(DUMMY_ID) ); DROP SEQUENCE DUMMY_SEQUENCE ; CREATE SEQUENCE DUMMY_SEQUENCE INCREMENT BY 1 START WITH 1 MAXVALUE 9999999999999999999999999999 MINVALUE 1 CACHE 20; CREATE OR REPLACE TRIGGER DUMMY_SEQUENCE_TRIGGER BEFORE INSERT ON DUMMY_TABLE FOR EACH ROW BEGIN < > BEGIN IF INSERTING AND :NEW.DUMMY_ID IS NULL THEN SELECT DUMMY_SEQUENCE.NEXTVAL INTO :NEW.DUMMY_ID FROM SYS.DUAL; END IF; END COLUMN_SEQUENCES; END; Here we have created a dummy table, a sequence and a trigger. On every insert on the table, the trigger will be called and next value of oour sequence will be the ID/Primary key of our table. Let us now se