一对一处理休眠双向关系

Question

I have two tables inside of my legacy application.

Host and Tables . Table Host has a foreign key relationship (Tables_fk) column with Tables . In my code I have a method as below.

public class Tables {
    public void addHosts(Host host) {
         getHostsCollection().add(host);
    }
}

Now I am splitting my database and Tables will go into a separate database. I am now dropping the column Tables_fk from Host and adding a column Table_ID there which I will write from my application. Now since I am writing the Table_ID to the host table from the application, I am guessing there is no need for the addHosts(Host host) mwthod to exist as of now.

Am I right? Also what does Hibernate add with that method since the Tables table does not have any foreign key relationship with Host .

Answer 1

First of all if you drop a table within your database, hibernate will no longer work for ManyToOne relationship (Table entity) so:

you need to remove your ManyToOne annotation within your Table class and then change it to @Transient or remove the hosts variable entirely together with getters and setters

And if you do so, your relationship is not Bi-Directional anymore , that relationship will become Uni-Directional and it works fine and you still can fetch all of your "tables" column rows!

Take note adding column is different with adding a Foreign Key and the section you have mentioned about dropping Tables_fk creates ambiguity