Oracle sets primary key auto-Increment

Oracle sets primary key auto-increment. Oracle does not have an auto-increment field. It can be indirectly implemented through sequence + trigger. In cmd, you can log on to sqlplus and run it directly. The steps below generally take place: 1. Create the data table Codecreate table Test_Increase (userid number (10) primary key,/* primary key, and automatically add */username varchar2 (20 )); 2. CREATE auto-increment sequence create sequence TestIncrease_Sequence increment by 1 -- add several start with 1 each time -- count NOMAXVALUE from 1 -- do not set the maximum value NOCYCLE -- always accumulate, no loop CACHE 10; 3. create trigger Test_Increase BEFOREinsert ON Test_Increase for each ROWbeginselect TestIncrease_Sequence.nextval into: New. userid from dual; end;