sql - 存储过程中表变量的复合主键

Question

我是存储过程新手，正在尝试向表变量添加复合主键。

DECLARE @statistictemp TABLE (
    MajorName      VARCHAR(50) NOT NULL, 
    SubName       VARCHAR(50) NOT NULL, 
    DetailedName   VARCHAR(50) NOT NULL, 
    UniversityID   SMALLINT    NOT NULL, 
    StatisticValue DECIMAL(9,3)
);

ALTER TABLE @statistictemp 
ADD CONSTRAINT pk_statistictemp 
PRIMARY KEY (MajorName, SubName, DetailedName, UniversityID);

我在 ALTER TABLE @statistictemp 上收到错误消息

Incorrect syntax near '@statistictemp'. Expecting ID, QUOTED_ID, or
'.'.

我在这里做错了什么？如何向表变量添加复合主键？

Answer 1

你可以这样做:

DECLARE @statistictemp TABLE (
    MajorName       VARCHAR(50) NOT NULL, 
    SubName        VARCHAR(50) NOT NULL, 
    DetailedName    VARCHAR(50) NOT NULL, 
    UniversityID    SMALLINT NOT NULL, 
    StatisticValue  DECIMAL(9,3),
    PRIMARY KEY (MajorName, SubName, DetailedName, UniversityID)
);

您可以通过尝试插入重复项来测试主键约束是否有效:例如，

INSERT INTO @statistictemp(MajorName, SubName, DetailedName, UniversityID) SELECT 'a','b','c',1
INSERT INTO @statistictemp(MajorName, SubName, DetailedName, UniversityID) SELECT 'a','b','c',1

第二条语句会抛出错误:

Msg 2627, Level 14, State 1, Line 13
Violation of PRIMARY KEY constraint 'PK_#1EA48E8_B595483D208CD6FA'. Cannot insert duplicate key in object 'dbo.@statistictemp'.
The statement has been terminated.