Oracle notes: Tables and fields (1)

Oracle notes: Tables and fields (1) 1. CREATE a TABLE: www.2cto.com first CREATE a TABLE and a field: create table mytable (id number (12) not null, NAME VARCHAR2 (32), DESP VARCHAR2 (100), age number (3 ), brithday date default sysdate) tablespace myspace; create a unique primary key: alter table mytable add constraint P_MT primary key (ID); Create a sequence for the ID: create sequence mysequence increment by 1 start with 1 nomaxvalue nocache; CREATE a TRIGGER: create or replace trigger mytrigger before insert on mytablefor each rowbeginif (: NEW. id is null) thenselect mysequence. nextval into: NEW. id from dual; end if; END; (sequence and trigger are created for ID auto-increment) after creating the table, you can run the DESC command to view: desc mytable;