CODEWITHSUNDEEP
hibernatepostgresqlormsequencehbm2ddl
newbie
newbie

Reputation: 24635

Hibernate is not auto creating sequencies to database when using auto creating of tables

I want to create my database tables automatically with Hibernate and Postgresql, but I get errors about sequences. Is it possible to auto create sequences too with Hibernate, or do I have generate sequences manually?

Example of my entity:

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;
import javax.persistence.UniqueConstraint;

@Entity
@Table(uniqueConstraints = { @UniqueConstraint( columnNames =  { "id" }) })
@SequenceGenerator(name="SEQ_EXAMPLE_ID", sequenceName="example_id_seq", allocationSize=1)
public class Example {

    @Id
    @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="SEQ_EXAMPLE_ID")
    private Long id;

    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public String g
}

Hibernate config:

hbm2ddl.auto=create-drop
hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect
hibernate.show_sql=true

Exceptions:

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.hibernate.exception.SQLGrammarException: could not get next sequence value

org.postgresql.util.PSQLException: ERROR: relation "example_id_seq" does not exist

Upvotes: 6

Views: 5610

Answers (4)

Ievgen
Ievgen

Reputation: 129

Here is my solution. Applicable for Postgres

<hibernate-mapping>

  <!-- ... -->

  <database-object>
    <create>CREATE SEQUENCE my_sequence</create>
    <drop>DROP SEQUENCE IF EXISTS my_sequence</drop>
  </database-object>

</hibernate-mapping>

Upvotes: 0

mrts
mrts

Reputation: 18925

You have to enable automatic schema creation in application.properties as described in Hibernate docs:

hibernate.hbm2ddl.auto = create

or when using Spring:

spring.jpa.hibernate.ddl-auto = create

But the general recommendation is not to use this in production, see Hibernate: hbm2ddl.auto=update in production?

Use database schema migration tools like Liquibase or Flyway instead.

Upvotes: 1

gogineni sameer
gogineni sameer

Reputation: 15

-We cant create sequences by using hbm2ddl property -we can create any number of tables any no of times but not sequence

sequence is db specific and we have to create our selves sequence in db

Upvotes: -2

Pascal Thivent
Pascal Thivent

Reputation: 570365

Your mapping seems correct and I suggest activating logging of the following category to see what is happening exactly:

  • org.hibernate.tool.hbm2ddl: Log all SQL DDL statements as they are executed

Set it to DEBUG and check the DDL statements (maybe update the question with the relevant parts).

PS: An allocationSize=1 is not very wise, using the default would be better. But that's unrelated.

References

Upvotes: 1

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