假设有学生S（学号，姓名，性别，入学时间，联系方式），院系D（院系号，院系名称，电话号码，负责人）和课程C（课程号，课程名）三个实体，若一名学生属于一个院系，一个院系有多名学生；一名学生可以选择多门课程，一门课程可被多名学生选择，则图中（a）和（b）分别为（ ）联系。假设一对多联系不转换为一个独立的关系模式，那么生成的关系模式（ ）。
问题1选项
A.1 *和1 *
B.1 *和* 1
C.1 *和* *
D.* 1和* *
问题2选项
A.S中应加入关系模式D的主键
B.S中应加入关系模式C的主键
C.D中应加入关系模式S的主键
D.C中应加入关系模式S的主键
正确答案及解析
正确答案
解析
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