问3表间的SQL关系

EN

CREATE TABLE Member
    ([MID] int primary key, [Name] varchar(5), [Address] varchar(8))
;

INSERT INTO Member
    ([MID], [Name], [Address])
VALUES
    (1, 'Name1', 'Address1')
;



CREATE TABLE Event
    ([EventNo] int primary key, [EventName] varchar(6))
;

INSERT INTO Event
    ([EventNo], [EventName])
VALUES
    (1, 'Event1')
;

    CREATE TABLE Attendance
        ([EventNo] int FOREIGN KEY REFERENCES Event(EventNo), [MID] int FOREIGN KEY REFERENCES Member(MID))
    ;

INSERT INTO Attendance
    ([EventNo], [MID])
VALUES
    (1, 1)
;

select * from Event join Attendance on Event.EventNo=Attendance.EventNo
join Member on Member.MID=Attendance.MID

create table member (
  MID INT primary key ...,
  Name VARCHAR(30),
  ...
);

create table event (
  EventNo INT primary key ...,
  EventName VARCHAR(30),
  ...
);

create table attenance (
  EventNo INT,
  MID INT,
  //here add constraint for MID and EventNo - they are  foreign key from other tables.
  UNIQUE(EventNo, MID)
);