hello

i facing a strange problem in my code.. first little bit explain my DB

i have Postgres DB in which have table Client,..
Client atble have fields like
clientID *sequence
ClientName *Filed
ClientEmail *Primary Key


now in hibernate i want to assign the generator name in the field ClientID

i using in Annotation fr mapping

bt when i do that


@Entity
@javax.persistence.SequenceGenerator(
name="SEQ_Client",
sequenceName="client_clientid_seq",
allocationSize=1)

@Table(name="client")
public class Client implements Serializable,Comparable<Client>{

@Id
private String businessname;

@Column(name="clientid")
@GeneratedValue(strategy=GenerationType.SEQUENCE, generator="SEQ_Client")
private Integer clientid;




but it not taking the sequence Generator on the Filed wheich is not a primary Key and not increment the value when i try to save data in Client table...

so help me out how i can set the Sequence Genrator on simple Filed in hibernate

waiting fr response....

i simply want to apply a generator on a Field which is not a Primary key is it possible becase i not seen any example in mapping in which the Sequence gerator is apply accept Primary Key....

kindly Guide me is that possibly to apply the Sequence Gerator on simple Field

waiting fr response

Standard hibernate/jpa generators are applied only to the entity identifiers.

I see at least two ways to go here:

Make your 'clientId' to be entity id and add if necessary UNIQUE constraint for the email column;

Introduce a db-level trigger that fills client id on new record insert;

The first option is much more preferable either for performance or db design characteristics.

hmmmm same thing i am doing now i change the primary key client id and set unique on businessEmail... but it is not a sulotion..... is there any way i use same mapping in hbm.xml file i mean doing same sequence in hbm files on non Primary key... if is it than show me the example how to set in hbm files..

thanx fr quick res...

can u tell me how that i can do in Postgres
Introduce a db-level trigger that fills client id on new record insert;



still waiting to resolve it

That is a solution. As I said before, orm generators work only with the entity ids, hence if you have a client id to be an entity id you can apply any suitable generator strategy. Also synthetic id looks like more convenient and efficient as a primary key than the user email.



Chapter 35. Triggers

I'm interested, why is that not a solution?
A unique email adress would qualify as a fine natural key, but how do you reference your user in other tables? by email adress or by clientid?

The former would be a rather bad idea usually...

just my 0.02€

sorry fr late rep i leave the office after my last reply...
hmmmmmm ok i agree with u abt the Primary key as a Client id...

bt still different question why it is a limitation in hibernate that we only set the Sequence only on Primart key... is there no alternative abt it... there are many situation in which we wanna use sequence on any field in Db so if use Hibernate than thats mean stuck on it....

ok one more point i got
if i simply run query and wanna add user than DB sequence work and increment bt when i try to save using Hibernate session.save(obj); than my filed value set to be null and not increment..

so there is only one solution that we run Custom made query from hibernate and not give filed (ClientID) it will automatically increment in DB side... so any alternative to reduce writing query headache

Don't know, but you can always do this in the database i guess.
Add a trigger that works on insert.

Maybe it's considered questionable design if you have another (unique) value in the same table thats assigned by sequence?
Because if you have one unique value you wouldn't need the other as primary key in the first place...



works fine for me with ID and GeneratedValue from Sequence

Did you found a way to use the hibernate sequence generator on a simple field? I didn't found any example about it. Do you change the primary key as they suggested?
[]'s

Map your property with generated="insert" and insert="false". Eg.



And then when you create your database table (PostgreSQL):

Nordborg, I'm using annotations but I resolved my problem with your post/help. I wasn't using "insertable=false" on @Column annotation.
Here is the code:

Java file:


SQL:


Thanks.

I have just declared



and code is declared as Integer.
schema is generated via ddl, and there is no autoincrement flag set, and in the end, no number is ever generated.
What am I missing?

How is the SQL code for your autoincrement field?