2个主表的子表 这样主键和外键的关系如何设置呢? 一个表是2个主表的子表 这样主键和外键的关系就不可以设置了 有高手指点如何解决么?例如 子表的parentid 一定是主表1的id或主表2的id的约束及其级联更新和删除的动作 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 --可以,假设A、B都是主表,关键字分别为id1,id2,子表为C,关键字为id,还有一个字段为pid,分别与A.id1、B.id2建立外键级联更新删除CREATE TABLE [A] ( [id1] [int] NOT NULL , CONSTRAINT [PK_A] PRIMARY KEY CLUSTERED ( [id1] ) ON [PRIMARY] ) ON [PRIMARY]GOCREATE TABLE [B] ( [id2] [int] NOT NULL , CONSTRAINT [PK_B] PRIMARY KEY CLUSTERED ( [id2] ) ON [PRIMARY] ) ON [PRIMARY]GOCREATE TABLE [C] ( [id] [int] NOT NULL , [pid] [int] NULL , CONSTRAINT [PK_C] PRIMARY KEY CLUSTERED ( [id] ) ON [PRIMARY] , CONSTRAINT [FK_C_A] FOREIGN KEY ( [pid] ) REFERENCES [A] ( [id1] ) ON DELETE CASCADE ON UPDATE CASCADE , CONSTRAINT [FK_C_B] FOREIGN KEY ( [pid] ) REFERENCES [B] ( [id2] ) ON DELETE CASCADE ON UPDATE CASCADE ) ON [PRIMARY]GO sorry 我忘记说明了一点 就是C表的pid是A表 或者是 B表的id 而不是同时是ab2个表的id,就是说pid不是a表的就是b表的id 但是 不一定同时是ab2个表的啊 所以 就难了 如何运算得知,由数字代表的是经过了几个月几天呢 一个表的记录怎么突然没有了?为什么 请邹老大帮忙,求一sql语句 请教一下这个函数定义错在哪? 存储过程在查询分析器里能执行,用作业怎么调用都是失败,怎么回事啊!!! 存储过程调用存储过程(返回两个数据集),如何获得被调用的存储过程的返回的两个数据集 SQL算术问题 数据库select问题!! 请问“insert和update”怎么才能同时把记录(插入/更新)到两个表?? 求一SQL语句 插入数据后表就打不开了---看来只有高手能回答了 查询bit字段的问题
[id1] [int] NOT NULL ,
CONSTRAINT [PK_A] PRIMARY KEY CLUSTERED
(
[id1]
) ON [PRIMARY]
) ON [PRIMARY]
GOCREATE TABLE [B] (
[id2] [int] NOT NULL ,
CONSTRAINT [PK_B] PRIMARY KEY CLUSTERED
(
[id2]
) ON [PRIMARY]
) ON [PRIMARY]
GO
CREATE TABLE [C] (
[id] [int] NOT NULL ,
[pid] [int] NULL ,
CONSTRAINT [PK_C] PRIMARY KEY CLUSTERED
(
[id]
) ON [PRIMARY] ,
CONSTRAINT [FK_C_A] FOREIGN KEY
(
[pid]
) REFERENCES [A] (
[id1]
) ON DELETE CASCADE ON UPDATE CASCADE ,
CONSTRAINT [FK_C_B] FOREIGN KEY
(
[pid]
) REFERENCES [B] (
[id2]
) ON DELETE CASCADE ON UPDATE CASCADE
) ON [PRIMARY]
GO
就是说pid不是a表的就是b表的id 但是 不一定同时是ab2个表的啊 所以 就难了