oracle添加主键的四种方法

张兴康

张兴康

racle添加

主键的四种方法:

列级，表级建立主键

drop table constraint_test;

1.create table constraint_test

( name_id number not null constraint cons_name_id primarykey,

old number )

2.create table constraint_test

( name_id number  primary key,

old number )

drop table constraint_test;

3.create table constraint_test

(

name_id number not null,

old number  ,

constraint cons_name_id primary key ( name_id)

);

drop table constraint_test;

4.create table constraint_test

(

name_id number not null,

old number   

);

alter table constraint_test add constraint cons_name_id primary key( name_id );

外键

drop table course ;

drop table students ;

create table students

(code number  ,

name varchar2(10),

country varchar2(30)

);

alter table students add constraint pk_st_cod primary key (code);

insert into studentsvalues(0001,'zhangsan','shanghai');

insert into studentsvalues(0002,'lisi','beijing');

insert into studentsvalues(0003,'wangwu','guangzhou');

create table course

(id number,

code  number,

name varchar2(10),

subject varchar2(30)

);

alter table course  add constraint pk_co_idprimary key ( id);

alter table course  add constraint fk_co_stforeign key ( code) references students(code);

alter table students add foreign key pk_co_id onid;

inser into course(id,code,name,subject)values(1,001,'zhangsan','yuwen');

inser into course(id,code,name,subject)values(2,001,'zhangsan','shuxue');

张兴康

张兴康