How to migrate a Hibernate NamingStrategy to (Implicit|Physical)NamingStrategy? Where is the documentation?

Question

The NamingStrategy was already being marked as deprecated in Hibernate 4.2/4.3 (HHH-7079). Starting with Hibernate 5, now it will shipped with two replacements(?) interfaces ImplictNamingStrategy and PhysicalNamingStrategy (HHH-7078) and have finally ditched support for the old NamingStrategy. That's why Spring's upcoming Hibernate5 supported has even removed the configurer namingStrategy() and favor of implicitNamingStrategy() and physicalNamingStrategy(). So far, so good.

Although it is mentioned in some documents (i.e. in the incomplete working-5.0-migration-guide.md) and in (generated) release notes for the upcoming Hibernate 5 (as of today), I've found no concrete example how to use these actually.

Perhaps I've missed something, but neither the JavaDoc nor the issues shows any evidence of the idea both strategy types. Furthermore I've already one strategy based on NamingStrategy: a custom OracleNamingStrategy which is based on the well-known one.

While I'm interested in a proper solution in code (obviously), the actual issue is getting a working migration document and/or the conceptual idea of the restructured naming strategy.

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Also related:

• ImprovedNamingStrategy no longer working in Hibernate 5

Tradition

You've already mentioned HHH-7078 there is also a link to HHH-9417 it describes the reason why they splitted the NamingStrategy. For the migration your existing OracleNamingStrategy must be modified so that it implements the PhysicalNamingStrategy. Was that your question? – Read

@Read Thank you. Well, is PhysicalNamingStrategy the "successor" of NamingStrategy? HHH-9417 explains the topic very shortly; yeah it could be helpful. I'm still not convinced about 2-3 lines in an issue of many (that's no documentation). – Tradition

I would not call it successor. It depends what's the intention to provide a different naming strategy. If you want to control how implicit names are generated than you'll have to implement the ImplicitNamingStrategy. If your intention is to control how implicit/explicit ames are mapped to physical db tables/columns than you'll have to implement the PhysicalNamingStrategy. If you need more information about the how and why you'll have to search the dev mailing list. Feel free to help them to update the documentation - it's an open source project. Contributors are welcome. – Read

Answer 1

Put below key value pair in your hibernate configuration file

hibernate.implicit_naming_strategy=org.hibernate.boot.model.naming.ImplicitNamingStrategyLegacyHbmImpl

hibernate.physical_naming_strategy=org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl

Rawhide

Answer 2

1. If you are providing @Table and @Column annotation in your entity classes with names provided with an underscore i.e. user_id i.e. @Column(name="user_id"), it will take the column name as user_id; if you give it as userid then it will change to user_id if you use no strategy or implicit strategy (specifically spring.jpa.hibernate.naming.implicit-strategy=org.hibernate.boot.model.naming.ImplicitNamingStrategyLegacyHbmImpl). So, if you want a strategy where the entity attribute name changes to one with underscore and lowercase letters i.e. something from userId to user_id, you should use implicit or no strategy (which actually uses implicit strategy).

2. If you don't want your naming strategy to add an underscore to the column name or class name, then the strategy that you need to use would look like: spring.jpa.hibernate.naming.physical-strategy=org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl. The things that you provide in annotations @Table and @Column’s name attribute would remain as it is.

3. If you don't want to provide annotations and want to manually handle the table name and column names, you should extend the class org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl and override the required methods. If you still use annotations for some of the cases here, remember the overridden methods will apply on the names written in those annotations.

   spring.jpa.hibernate.naming.physical-strategy=example.CustomStrategy

Morbilli