如何在具有多列的 sql 服务器中创建外键？

Question

i'm trying to create foreign key:

create table visit
      (Num_vst int primary key,
      date_vst date,
      num_agnt int,
      code_type int,
      Constraint fk_vst foreign key (num_agnt,code_type) 
        references agente,type_de_verification  (num_agnt,code_type);

where is the problem?

Answer 1

You are describing two separate relationships to two tables:

num_agnt is related to agente and code_type is related to type_de_verification

In this case you can define both foreign keys as shown below:

create table visit (
  Num_vst int primary key,
  date_vst date,
  num_agnt int,
  code_type int,
  constraint fk1 foreign key (num_agnt) references agente (num_agnt),
  constraint fk2 foreign key (code_type)
    references type_de_verification (code_type)
);