Oracle Creating Primary Keys
We just created this table:
CREATE TABLE DEPENDENTS
( "ID" NUMBER(6,0)not null,
"FIRSTNAME" VARCHAR2(20),
LASTNAME VARCHAR2(20),
BIRTHDATE DATE,
RELATION VARCHAR2 (25),
GENDER VARCHAR2(1),
BENEFITS CLOB,
RELATIVEID VARCHAR2(10) );
So we need to add a primary key linked to ID field doing:
ALTER TABLE DEPENDENTS add CONSTRAINT DEPENDENTS_PK PRIMARY KEY(ID) ;
table altered.
We also want to create a data sequence for populating the ID field:
CREATE SEQUENCE DEPENDENTS_SEQ MAXVALUE 999 MINVALUE 1;
Now we can use this sequence to enter ID value "by default":
create or replace trigger bi_dependents
before insert on dependents
for each row
begin
select DEPENDENTS_SEQ.nextval into :NEW.ID from dual;
end;
page revision: 4, last edited: 20 Mar 2012 14:51