testRequest (wardNo nchar(5), BHTNo nchar(5), testID nchar(5), reqDateTime datetime);

ALTER TABLE dbo.testRequest
ADD CONSTRAINT PK_TestRequest
PRIMARY KEY (wardNo, BHTNo, TestID)

CREATE TABLE testRequest (
        wardNo nchar(5),
        BHTNo nchar(5),
        testID nchar(5),
        reqDateTime datetime,
        PRIMARY KEY (wardNo, BHTNo, testID)
);