CODEWITHSUNDEEP
oracle-databasehibernate
Ula Krukar
Ula Krukar

Reputation: 12999

What does hibernate do with generator class="native" on oracle db?

I have this mapping in my code:

News.hbm.xml:
<class name="xyz.News" table="XYZ_NEWS">
        <id name="id" column="NEWS_ID">
            <generator class="native"/>
        </id>
rest of mapping
</class>

I am using Oracle database. Hibernate documentation tells me:

native - selects identity, sequence or hilo depending upon the capabilities of the underlying database

What does that mean for Oracle?

Edit: I know now it uses sequences. The name of the sequence is what i am interested in.

Upvotes: 3

Views: 23461

Answers (2)

Stefan Steinegger
Stefan Steinegger

Reputation: 64628

It takes sequences. You need to provide a sequence name.
Edit: If name is not provided, sequence named HIBERNATE_SEQUENCE is going to be used.

Looking at the code, it lets the dialect decide. The Dialect implements the decision like this:

// Dialect.cs Line 231
public virtual System.Type NativeIdentifierGeneratorClass
{
    get
    {
        if (SupportsIdentityColumns)
        {
            return typeof(IdentityGenerator);
        }
        else if (SupportsSequences)
        {
            return typeof(SequenceGenerator);
        }
        else
        {
            return typeof(TableHiLoGenerator);
        }
    }
}

It isn't overriden by Oracle. Oracle doesn't support identity, but sequences.

Upvotes: 8

danny.lesnik
danny.lesnik

Reputation: 18639

It's quite simple: Your generator will use identity or sequence columns according to what your current database support:

For example Oracle has sequences but previous versions of MS SQL server don't.

You can read more about differences between identities and sequences in this article: http://sqlserver-training.com/what-is-the-difference-between-identity-and-sequence/-

The native generator always returns long, short or integer values:

Upvotes: 1

Related Questions