添加外鍵

alter table CodeInfo drop constraint FK_CodeInfo_CodeCa

alter table CodeInfo add  constraint FK_CodeInfo_CodeCa  foreign key(CategoryID) references CodeCategory(CategoryID)



create table CodeInfo

(

    CodeID int identity(1,1) primary key

    ,CategoryID varchar(8) references CodeCategory(CategoryID)

    ,CodeName nvarchar(8)

)