某企业的数据库系统中有如下所示的员工关系和仓库关系,每个仓库可有多名员工,但只有一名负责人。
员工关系(employee):
员工编号 (employeeID) | 员工姓名 (name) | 部门 (department) | 职务 (position) |
001 | 李蕾 | 仓储部 | 组长 |
002 | 张明 | 仓储部 | 组长 |
003 | 何苗 | 仓储部 | 保管员 |
仓库编号 (warehouseID) | 仓库名称 (name) | 地址 (address) | 负责人编号 (pricipalID) |
01 | 仓库A | 地址A | 001 |
02 | 仓库B | 地址B | 002 |
03 | 仓库C | 地址C | 003 |
A.CREATE TABLE (employee ID CHAR(2)NOTNULL UNIQUE,
name CHAR(30)NOT NULL,
address CHAR(40),
principal ID CHAR(3));
B.CREATE warehouse(warehouse ID CHAR(2)PRIMARY KEY,
name CHAR(30),
address CHAR(40),
principal ID CHAR(3));
C.CREATE TABLE warehouse(warehouse ID CHAR(2)PRIMARY KEY,
name CHAR(30)NOT NULL,
address CHAR(40),
principal ID CHAR(3),
FOREIGN KEY(principal ID)REFERENCES employee(employee ID));
D.CREATE TABIE warehouse(warehouse ID CHAR(2),
name CHAR(30)NOT NULL,
address CHAR(40),
principal ID CHAR(3),
PRIMARY REY(warehouse ID),
FOREIGN KEY(employee ID)REFERENCES employee(employee ID));
参考答案:C