How do I configure JPA table name at runtime?

Question

I have an issue where I have only one database to use but I have multiple servers where I want them to use a different table name for each server.

Right now my class is configured as:

@Entity
@Table(name="loader_queue")
class LoaderQueue

I want to be able to have dev1 server point to loader_queue_dev1 table, and dev2 server point to loader_queue_dev2 table for instance.

Is there a way i can do this with or without using annotations?

I want to be able to have one single build and then at runtime use something like a system property to change that table name.

Take a look here: [link](http://stackoverflow.com/questions/3879607/change-table-name-of-an-entity-on-runtime) — Shelltux, Jun 22 '15 at 18:49
Your best bet is to create an alias/synonym/view in the database which is the same on each server. — DuncanKinnear, Jun 22 '15 at 19:45

Vlad Mihalcea · Accepted Answer · 2018-04-19T09:08:10.277

5

For Hibernate 4.x, you can use a custom naming strategy that generates the table name dynamically at runtime. The server name could be provided by a system property and so your strategy could look like this:

public class ServerAwareNamingStrategy extends ImprovedNamingStrategy {

    @Override
    public String classToTableName(String className) {
        String tableName = super.classToTableName(className);
        return resolveServer(tableName);
    }

    private String resolveServer(String tableName) {
        StringBuilder tableNameBuilder = new StringBuilder();

        tableNameBuilder.append(tableName);
        tableNameBuilder.append("_");
        tableNameBuilder.append(System.getProperty("SERVER_NAME"));

        return tableNameBuilder.toString();
    }
}

And supply the naming strategy as a Hibernate configuration property:

<property 
    name="hibernate.ejb.naming_strategy" 
    value="my.package.ServerAwareNamingStrategy"
/>

edited Apr 19 '18 at 09:08

answered Jun 23 '15 at 05:14

Vlad Mihalcea

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Thanks for the info, i assume this is hibernate specific. Also, How do I specify my entity to use this naming strategy? Right now I just have the Entity and Table annotations. Do i need to use some XML config? Or can it go in my entity manager XML config somewhere? – Rocky Pulley Jun 23 '15 at 21:07
It can go in the persistence.xml file but it applies to all Entities. – Vlad Mihalcea Jun 23 '15 at 21:17
Hi @VladMihalcea: We had a use case where we get the table suffix via batch cmd line arg. We thought we could try this approach. Will this work in Hibernate 5 and are there better ways to do it now ? Thanks in advance.. ! – Mithun Sasidharan Oct 30 '20 at 17:09

score 2 · Answer 2 · answered Jun 23 '15 at 04:40

I would not do this. It is very much against the grain of JPA and very likely to cause problems down the road. I'd rather add a layer of views to the tables providing unified names to be used by your application.

But you asked, so have some ideas how it might work:

You might be able to create the mapping for your classes, completely by code. This is likely to be tedious, but gives you full flexibility.
You can implement a NamingStrategy which translates your class name to table names, and depends on the instance it is running on.
You can change your code during the build process to build two (or more) artefacts from one source.

How do I configure JPA table name at runtime?

2 Answers2

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