sql - 表 A 的 PK 被表 B 的 FK 引用。不能丢弃表 A 的 PK

Question

微软 SQL 服务器

我正在制作一个星型模式。我已经设置了 PK's和 FK对于我的表，现在我正在尝试编写一个过程，该过程将删除约束、截断表、再次添加约束，然后重新填充表。当我尝试删除约束时，我收到错误:

“约束 PK_TIMEDIM 被表 SalesFactTable 引用，外键约束 FK_SALESFACTTABLE 。无法删除约束。”

编辑:一个问题解决了。另一个发现。我收到同样的错误，除了现在有神秘的自动生成 FK's如 FK__SalesFact__CUST___19DFD96B .

请告诉我我做错了什么。

ALTER PROCEDURE [dbo].[A11]
AS
BEGIN

--Drop constraints
ALTER TABLE SalesFactTable
DROP CONSTRAINT FK_SALESFACTTABLE

ALTER TABLE SalesFactTable
DROP CONSTRAINT PK_SALESFACTTABLE

ALTER TABLE TimeDim
DROP CONSTRAINT PK_TIMEDIM

ALTER TABLE CustomerDim
DROP CONSTRAINT PK_CUSTOMERDIM

ALTER TABLE PartDim
DROP CONSTRAINT PK_PARTDIM

--Truncate tables
TRUNCATE TABLE TimeDim
TRUNCATE TABLE CustomerDim
TRUNCATE TABLE PartDim
TRUNCATE TABLE SalesFactTable

--Add constraints
ALTER TABLE TimeDim
ADD CONSTRAINT PK_TIMEDIM PRIMARY KEY (TIME_ID)

ALTER TABLE CustomerDim
ADD CONSTRAINT PK_CUSTOMERDIM PRIMARY KEY (CUST_ID)

ALTER TABLE PartDim
ADD CONSTRAINT PK_PARTDIM PRIMARY KEY (PART_ID)

ALTER TABLE SalesFactTable
ADD CONSTRAINT FK_SALESFACTTABLE FOREIGN KEY (TIME_ID) REFERENCES TimeDim (TIME_ID),
FOREIGN KEY (CUST_ID) REFERENCES CustomerDim (CUST_ID),
FOREIGN KEY (PART_ID) REFERENCES PartDim (PART_ID)

ALTER TABLE SalesFactTable
ADD CONSTRAINT PK_SALESFACTTABLE PRIMARY KEY (TIME_ID, CUST_ID, PART_ID)

Answer 1

**外键是由主键引用的，所以在去掉外键约束之前是不允许先去掉主键的。
因此，您需要先删除外键才能从表中删除主键约束。

**

ALTER PROCEDURE [dbo].[A11]
AS
BEGIN
  --Drop FK constraints
ALTER TABLE SalesFactTable
DROP CONSTRAINT FK_SALESFACTTABLE
    --Drop PK constraints
ALTER TABLE SalesFactTable
DROP CONSTRAINT PK_SALESFACTTABLE

ALTER TABLE TimeDim
DROP CONSTRAINT PK_TIMEDIM

ALTER TABLE CustomerDim
DROP CONSTRAINT PK_CUSTOMERDIM

ALTER TABLE PartDim
DROP CONSTRAINT PK_PARTDIM

--Truncate tables
TRUNCATE TABLE TimeDim
TRUNCATE TABLE CustomerDim
TRUNCATE TABLE PartDim
TRUNCATE TABLE SalesFactTable

--Add constraints
ALTER TABLE TimeDim
ADD CONSTRAINT PK_TIMEDIM PRIMARY KEY (TIME_ID)

ALTER TABLE CustomerDim
ADD CONSTRAINT PK_CUSTOMERDIM PRIMARY KEY (CUST_ID)

ALTER TABLE PartDim
ADD CONSTRAINT PK_PARTDIM PRIMARY KEY (PART_ID)

ALTER TABLE SalesFactTable
ADD CONSTRAINT FK_SALESFACTTABLE FOREIGN KEY (TIME_ID) REFERENCES TimeDim (TIME_ID),
FOREIGN KEY (CUST_ID) REFERENCES CustomerDim (CUST_ID),
FOREIGN KEY (PART_ID) REFERENCES PartDim (PART_ID)

ALTER TABLE SalesFactTable
ADD CONSTRAINT PK_SALESFACTTABLE PRIMARY KEY (TIME_ID, CUST_ID, PART_ID)