Hibernate，如何建模这种关系

问题描述

  create table logical_id_seq（
 logical_id int auto_increment，
 primary key（logical_id）
）; 
 
 create table mytable（
 physical_id int auto_increment，
 logical_id int not null引用parent（logical_id），
 data varchar（20），
主键（physical_id）
）; 
  

第二个表格使用第一个表格自动生成的值作为其值。我不知道如何在休眠模型中进行建模。

我读过，但我doesn看起来很难理解。

解决方案

实际上很难说，我不知道你想在对象中表达什么级别：它是一对一的外键关联吗？多对一的关联？协会是双向的吗？使用ORM意味着思考对象不仅仅是表格，它通常有助于提供对象模型。

我假设这是一对一的外键关联。以下是 Java与Hibernate的持久性建议：

如果你真的有一个真正的多对一关联，应该很容易适应上述解决方案。

I have the below tables.

create table logical_id_seq (
    logical_id int auto_increment,
    primary key(logical_id)
);

create table mytable (
    physical_id int auto_increment,
    logical_id int not null references parent(logical_id),
    data varchar(20),
    primary key(physical_id)
);

The second table uses first table auto-generated value as its value. I am not sure how to model this in hibernate.

I read http://docs.jboss.org/hibernate/core/3.3/reference/en/html/mapping.html#mapping-declaration-onetoone, but I doesn't seem to understand.

解决方案

It's actually hard to say, I don't know what you want to represent at the object level: is it a one-to-one foreign key association? a many-to-one association? is the association bi-directional? Using an ORM means thinking objects more than tables and it usually help to provide the object model.

I'll assume this is a one-to-one foreign key association. Here is what Java Persistence with Hibernate recommends:

If what you have is actually a real many-to-one association, it should be pretty easy to adapt the above solution.

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