What is the candidate key of a relational database ( )

题库:计算机等级考试 类型:最佳选择题 时间:2017-07-03 16:34:33 免费下载:《单选题》Word试卷

What is the candidate key of a relational database ( )
A.Fields from multiple tables that are used for sorting records
B.A set of fields in a table used to identify a record uniquely
C.A field with a constraint placed on it
D.A set of fields that have no data in them

本题关键词:僵a,ECF-A,EP21-A,EP6-A,EP18-A,EP7-A,Lp(a),Lp（a）,A-aDO2,抗A;