求助SQL问题
create table s1(sno char(8) not null,
sname char(10),
ssex char(2)
)
alter table s1
add constraint pk_sno primary key(sno)
alter table s1
add constraint uk_cno unique(sname)
alter table s1
add constraint df1_ssex default'男'for ssex
create table c1
(sno char(8) not null,
cno char(8) not null,
score int
)
alter table c1
add constraint pk_c1 primary key(sno)
alter table c1
add constraint pk_c2 primary key(cno)
alter table c1
add constraint fk_sno foreign key references s1(sno)
alter table c1
add constraint score_chk check(score>=0 and score<=100)
执行后出现
消息 8139，级别 16，状态 0，第 22 行
表 'c1' 的外键中引用列的数目与被引用列的数目不等。 alter table c1
add constraint pk_c1 primary key(sno)
alter table c1
add constraint pk_c2 primary key(cno)
alter table c1
-------------------------》how could one table has two primary key?? As far as i know that one table having two primary keycould never happen in Oracle!
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