hibernate ORM 对应关系

A 一对多 classes—->student (one—>many）

单向：
           

one

public class Classes {

private Integer id;

private String name;

private Set students; 在一的一方保存多的集合

}

many

public class Student {

private Integer id;

private String name;

}

B 多对一

单向

many

public class Student {

private Integer id;

private String name;

private Classes classes;在多的一方保留一的引用

}

one

public class Classes {

private Integer id;

private String name;

}

双向 一对多（one to many) / 多对一（many to one）
           

many

public class Student {

private Integer id;

private String name;

private Classes classes; 在多的一方保留一的引用

}

one

public class Classes {

private Integer id;

private String name;

private Set students; 在一的一方保存多的集合

}

多对多

单向

many1

public class Role{

private Integer id;

private String name;

private Set users; 在任一方保留对方的set

}

many2

public class User{

private Integer id;

private String name;

}

双向

many1

public class Role{

private Integer id;

private String name;

private Set users; 在两一方保留对方的set

}

many2

public class User{

private Integer id;

private String name;

private Set roles;在两方保留对方的Set

}