A.字段名、數(shù)據(jù)類型、數(shù)據(jù)約束 B.字段名、數(shù)據(jù)完整性 C.字段名、數(shù)據(jù)類型、數(shù)據(jù)寬度 D.字段名、變量、作用域
A.STUDENT B.XS C.C D.3
A.2345.278B.2345.27C.345.278D.2345.28