Question

CREATE TABLE Room（ RoomID nvarchar（8）PRIMARY KEY，容量数字（3）

）

CREATE TABLE RoomType（ RoomType nvarchar（2）主键，描述nvarchar（20），责任nvarchar（20））

alter table Room

添加约束fk_type外键（Type）引用RoomType（Type）

主要错误0x80040E11，次要错误0

改变房间添加约束fk_type外键（类型）引用RoomType（Type）列ID无效。 [类型]

Answer 1

您可以创建一个RoomEquipment表，它将RoomID和EquipmentType组合在一起，如下所示：

create table RoomEquipment (
  RoomID int,
  EquipmentType nvarchar(1),
  primary key (roomid, equipmenttype),
  constraint fk_roomequipment_equipment_type 
             foreign key (equipmenttype) 
             references equipment(equipmenttype),
  constraint fk_roomequipment_equipment_roomid
             foreign key (roomid) 
             references room(roomid)
);

其他表格可能如下所示：

-- I prefer using char datatype for predictable number of characters in a field
CREATE TABLE RoomType (
Roomtype nvarchar(2) NOT NULL,
Description nvarchar(20),
Responsibility nvarchar(20),
primary key (Roomtype)
);

-- You could use char(1) instead of nvarchar(1) for type; I'd prefer using int instead
create table Equipment (
Equipmenttype nvarchar(1) NOT NULL,
Description nvarchar(10)
);

-- Added a unique key to assist with good foreign key relationship
alter table Equipment add constraint uk_equipment_equipmenttype unique (equipmenttype);

-- Just use an int or char if roomID length is predictable
Create table Room (
RoomID nvarchar(8),
Capacity numeric(3),
Roomtype(fk,nvarchar(2)
);

alter table room add constraint uk_room_id unique (roomid);

示例在这里：http://sqlfiddle.com/#!3/f510b

尝试在sql中创建外键时继续出错？

1 个答案: