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Hibernate 5 ID AUTO Generation Type for Oracle as Sequence and MySQL as Identity

We have a Java program using Hibernate 5 that can be installed using different DB Engines: Oracle, PostgreSQL or SQL Server. Now we are introducing MySql.
The entities have a Generated Value AUTO identifier.
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
protected Long id;
This worked fine until now. Oracle and PostgreSQL installations are using HIBERNATE_SEQUENCE sequence to generate the id values and SQL Server is using a table generated id (IDENTITY).
With MySQL we would like to use also the table generated id, but Hibernate 5 GenerationType.AUTO on MySQL tries the TABLE generator instead of the IDENTITY generator.
I found this solution by Vlad Mihalcea where using a native generator makes Hibernate to select IDENTITY for MySQL:
#Id
#GeneratedValue(strategy = GenerationType.AUTO, generator = "native")
#GenericGenerator(name = "native", strategy = "native")
protected Long id;
That's nice for MySQL, but then the application is no longer working in Oracle (ORA-02289: sequence does not exist). I think Hibernate is then searching for a sequence called native in the Oracle DB.
Is there a solution to keep the ID generation the same for all the other DB engines (Oracle, PostgreSQL and SQL Server) and use the IDENTITY for MySQL?
If not the only solution I can see is to implement the TABLE ID generation in MySQL, but it seems not to have a good performance.

I almost had it in the question, but in case somebody falls in the same situation: calling the generator HIBERNATE_SEQUENCE will make it backwards compatible with Oracle and PostgreSQL (SQL Server will continue using IDENTITY).
#Id
#GeneratedValue(strategy = GenerationType.AUTO, generator = "HIBERNATE_SEQUENCE")
#GenericGenerator(name = "HIBERNATE_SEQUENCE", strategy = "native")
protected Long id;

Hey this question/answer got me on the road to the answer. I am using Hibernate core 5.4.30 with MSSQL SQLServer2012Dialect and Oracle Oracle12cDialect. I needed to use the #GenericGenerator annotation as well for it's native strategy. maybe I could have used this directly with #GeneratedValue? anyway...
I found Oracle did not come with a sequence named HIBERNATE_SEQUENCE, and even when I added one, hibernate was still giving me sequence not found errors, seemingly having to do with my schema... So you can make things more specific like this:
#Id
#GenericGenerator(name = "MY_SEQUENCE", strategy = "native",
parameters = {
#org.hibernate.annotations.Parameter(name = "schema", value="MY_SCHEMA"),
#org.hibernate.annotations.Parameter(name = "sequence_name", value="MY_SEQUENCE")
}
)
#GeneratedValue(generator = "MY_SEQUENCE")
private Long id;
Hypothetically the name of the #GenericGenerator only has to match the generator name in the #GeneratedValue, but I made it the same as my actual database sequence for simplicity.

Set AllocationSize in Generic Generator native strategy

I have a java spring boot project which needs to be run on both MySQL and Oracle databases. The project has multiple entities with primary keys set to auto-increment in the db.
I have identified that Hibernate's #GenericGenerator in native strategy will support both MySQL (as IDENTITY) and Oracle (as SEQUENCE) in terms of auto-increment depending on the type of db. But I can't seem to find how to set the allocationSize in the GenericGenerator, for an oracle sequence. I want the allocationSize to be set to 1.
#Id
#GeneratedValue(strategy = GenerationType.AUTO, generator="gen")
#GenericGenerator(name = "gen", strategy = "native")
#Column(name = "id", nullable = false)
private Long id;
//Getter and Setter

#GenericGenerator is a hibernate annotation used to denote a custom generator, which can be a class or shortcut to a generator supplied by Hibernate. increment is a shortcut to a Hibernate generator.
check this link below: - Hibernate, #SequenceGenerator and allocationSize

Oracle JPA GenerationType.AUTO with generator asks for "hibernate_sequence"

I'm trying to use a defined sequence generation in Oracle JPA, along with GenerationType.AUTO like this:
#Id
#SequenceGenerator(name = "MY_GEN_NAME", sequenceName = "MY_SQ_NAME")
#GeneratedValue(strategy = GenerationType.AUTO, generator = "MY_GEN_NAME")
#Column(name = "ID", nullable = false)
private Long id;
After running the hibernate validation it throws an error:
Schema validation: missing sequence [hibernate_sequence]
I guess, it is ignoring my MY_GEN_NAME and trying to use that global sequence for id generation.
When I switch to GenerationType.SEQUENCE, it uses SequenceHiLoGenerator and it works fine.
Why is that happening, and is it possible to make the GenerationType.AUTO work with given sequence for Oracle (possibility to switch to other db)?

AUTO says to the JPA provider, "choose what you want", and it will not use the "generator" attribute in that case.
If you want to use a SEQUENCE then set the strategy to SEQUENCE! That way it will use the sequence definition you have defined

Though hibernate-sequence-on-oracle-generatedvaluestrategy-generationtype-auto suggests that this will work, it appears that it is broken for some versions of Hibernate, see HHH-10656.
Edit: Broken in 5.2.0, unbroken in 5.2.8.

Is it possible to create and use sequence generator in JPA / Hibernate without a column?

I'm using JPA (Hibernate) and I want to create a sequence for example like this.
CREATE SEQUENCE my_seq
INCREMENT 1
MINVALUE 1
MAXVALUE 999999
START 1;
This sequence shouldn't be assigned to a special column or table. I just want to be able to query the next value:
SELECT nextval('my_seq')
By doing this I would have a nice possibility to generate unique ids for anything i like.
Btw: I'm using Hibernate 4.2 and PostgreSQL 9.3

#Entity
public class Event implements Serializable {
#SequenceGenerator(name="Event_Seq", sequenceName="Event_Seq", initialValue = 1, allocationSize = 1)
#GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "Event_Seq")
#Id
private Long id;
}
You can create Event_Seq by script or leave it for Hibernate to create (provided you are using schema generation). You also need DB that is supporting sequences.

Problem with HSQLDB & SequenceGenerator

I have an entity which has an ID field:
#Id
#Column(name = "`U##ID_VOIE`")
#GeneratedValue(generator = "VOIE_SEQ")
private String id;
The class has the sequence generator defined as well:
#SequenceGenerator(name = "VOIE_SEQ", sequenceName = "VOIE_SEQ")
and the Oracle schema has the requisite sequence present. Everything works okay.
We also have tests, which uses an in-memory HSQLDB. Before running the tests, all the tables are created based on the Hibernate entity classes.
However the table for this particular class is not being created. And error pops up, because ID is a String and the SequenceGenerator in HSQLDB returns an INT / LONG / Numeric value.
The application is using a legacy Oracle database and ID_VOIE column must remain a String / Varchar.
Any solutions?

Using H2 instead.