problem of generating a primary key

gefeiChen · **Joined:** Thu Dec 22, 2005 11:15 pm **Posts:** 13

Hi,

I use JDK1.4.1 + hibernate-3.1 + oracle9.

The section of mapping file for generating a primary key is as following:

Code:

<generator class="seqhilo">
   <param name="sequence">HIBERNATE_UNIQUE_KEY</param>
   <param name="max_lo">100</param>
</generator>

I have already create a table named "HIBERNATE_UNIQUE_KEY" with a field named "nextval". DataType of nextval is number(38).

When I save the object, the exception says as following:

Code:

Hibernate: 
    select
        GDW2.HIBERNATE_UNIQUE_KEY.nextval 
    from
        dual
20:07:17,307  WARN JDBCExceptionReporter:71 - SQL Error: 2289, SQLState: 42000
20:07:17,307 ERROR JDBCExceptionReporter:72 - ORA-02289: serial(number) does not exist
org.hibernate.exception.SQLGrammarException: could not get next sequence value
   at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:65)

Could anyone tell me how to set the parameters and environment for
<generator class="seqhilo">?

And, is it imperative that I should create several tables for several entities which need a generated key? Is there anyway to share the sequence table with different fields?

Also, in my environment, what is the most efficient algorithm?

Thanks in advance.

Hector_Lopez · **Posted:** Fri Dec 23, 2005 5:12 am

I'm using PostgreSQL but i really doubt you can do that with a table. Sequence numbers in postgre are created as follows:

CREATE SEQUENCE hibernate_sequence
INCREMENT 1
MINVALUE 1000
MAXVALUE 9223372036854775807
START 1000
CACHE 1;

Try searching for sequence syntax in oracle.

Hope this helps.
Bye.

crista · **Posted:** Fri Dec 23, 2005 6:38 am

What I'm using to generate a primary key on Oracle is:

<generator class="native">
<param name="sequence">SEQUENCE_NAME</param>
</generator>

and I create the sequence into Oracle db schema using CREATE SEQUENCE... command.

That's all.

Cristian.

chen_yulei · **Joined:** Tue Nov 01, 2005 5:21 am **Posts:** 24

You might also use seqhilo, while the sequence_name is the name of sequence.