??????????
????—-??????? (Primay Key Constraint) ??  ????????
????—-??? (Unique Constraint)            ???????????????????
????—-?????? (Check Constraint))            ???????????Χ???????????(?磺????????)
????—-?????? (Default Constraint)            ???????????
????—-?????? (Foreign Key Constraint)     ????????????????????????????
?????????????????
????—-??????????????stuNo?????????
????alter table stuInfo
????add constraint PK_stuNo primary key (stuNo)
????—-????????????????????????????????
????alter table stuInfo
????add constraint UQ_stuID unique(stuID)
????—-????????????????????? ????“???????”??
????alter table stuInfo
????add constraint DF_stuAddress default (‘???????’) for stuAddress
????—-???????? ?????????????? 15-40?????
????alter table stuInfo
????add constraint CK_stuAge check (stuAge between 15 and 40)
????alter table stuInfo
????add constraint CK_stuSex check (stuSex=’??’ or stuSex=’?′)
????—-????????? (????stuInfo????stuMarks????????????????stuNo)